How-To Geek

Ask How-To Geek: Why You Should Never Vacuum Your PC, Converting Books for the Kindle, and Controlling Multiple Computers with One Keyboard


You’ve got questions and we’ve got answers. Today we take a look at why you should never vacuum your dusty PC, how covert books to read on the Kindle, and how to control multiple computers with one keyboard and mouse.

Cleaning Out Your Dusty PC sans Vacuum Cleaner


Dear How-To Geek,

I’ve heard from more than one person that it’s a bad idea to vacuum out the inside of your PC… but why? I’d like to get to the bottom of things before I accidently destroy my computer.


Dusty in Delaware

Dear Dusty,

It’s bad to clean the inside of your computer with a vacuum cleaner because vacuuming creates a large static build up that could (and most likely will) discharge into the sensitive electronics inside your computer case. There are specialized vacuum cleaners designed for cleaning out computers and electronic equipment but given the limited amount of use a single user would get from such a purchase it’s not a very wise one—they start at $300+ and can easily break the $1000 price barrier.

What we’d recommend doing is taking your computer case into a well ventilated area (outside on a sunny day or in your garage is a great place), grounding the case to protect against static discharge (although the risk here is very very low) and using compressed air to clean the dust off. If you’re using an air compressor (as opposed to just a can of compressed air from the computer store) make sure to start a good 24″ or so away from the case and work your way in closer. You want to use just enough air pressure to blast the dust off the surfaces and out of the case without overdoing it and pushing dust into even more difficult to remove places.

One important thing to consider: compressed air (from a compressor, not a can) contains minute amounts of water vapor. Although we’ve never actually heard of this happening to anyone it is (however remote the chance) possible to blow moisture into the connectors on your mother board and damage it if you were to boot it immediately afterwards. This is in the range of lightening-strike remote, however. None the less to be extra cautious we would recommend that you leave the computer off and in a warm dry location for a few hours after you give it a good air-compressor cleaning to allow any residual moisture (if it’s even there to begin with) to evaporate. This borders on paranoid caution, mind you, but better safe than sorry.

Converting Books for the Kindle


Dear How-To Geek,

I need to be able to convert ePub books into AZW books so that I can read them on my Kindle. How can I do this? Also, is there an easy way to remove DRM from ePub and AZW documents? Thanks!


Formats, Conversions, and DRM, Oh my!

Dear Formats,

There are applications out there that will convert documents into AZW format. They’re usually quite specialized (such as just converting one particular format like PDF to AZW) and often not particular effective. That’s not a problem though! Kindles read the MOBI format quite nicely and it’s very easy to convert to the MOBI format. We’d suggest downloading a copy of the excellent open source application Calibre and using that to manage all your non-Amazon purchases on your Kindle. From within Calibre you can convert from many formats into MOBI (including from ePub to MOBI).

As for stripping DRM from ePub and AZW books, it’s a royal pain in the ass. ePub encryption schemes vary quite widely from publisher to publisher and AZW DRM stripping used to be just a moderate pain in the ass but is now a huge pain in the ass thanks to Amazon’s institution of per-book keys (instead of using universal keys). Decrypting and stripping the DRM is pretty much a case-by-case basis and not worth the effort unless you’re trying to strip the DRM off a book to use on another device and you can’t find a copy of it from the “usual sources”, if you will. Sorry there isn’t an easy solution! DRM is an enormous pain.

Controlling Multiple Computers via One Keyboard and Mouse


Dear How-To Geek,

I have my desktop with Windows 7 and 2 monitors. I would like to setup another rig right next to it, and install Ubuntu on it. I would then like to use a KVM switch and/or software, and be able to hotswap operate either OS on both monitors, or Windows on one and Ubuntu on the other. How can I achieve this one keyboard, one mouse, dual machine nirvana?


Attempting Omnicontrol in Omaha

Dear Omnicontrol,

You’re in luck. This is one of those geek moments where a perfectly elegant, robust, and free solution exists. You need a copy of Synergy. Synergy is an awesome application that allows you to control multiple machines using a single keyboard and mouse input. One of your machines acts as the server and the rest of the machines act as clients. It’s quite snappy and a solution well loved by geeks of all stripes. It’s free, open source, and works on Windows, Mac, and Linux machines.

Have a burning question? Shoot us an email at and we’ll do our best to get you an answer!


Jason Fitzpatrick is a warranty-voiding DIYer who spends his days cracking opening cases and wrestling with code so you don't have to. If it can be modded, optimized, repurposed, or torn apart for fun he's interested (and probably already at the workbench taking it apart). You can follow him on if you'd like.

  • Published 04/4/11

Comments (65)

  1. Hatryst

    Believe, me, I was just looking up on Google for ‘Convert ebooks to Kindle’, and wished HTG would’ve covered this…
    Nothing more needs to be said :D

  2. brssnkl

    tootbrush is the best for cleaning old computers :D

  3. Alex

    Cleaning out old PCs with canned air or a compressor can be dsangerous if you “Zip” the fan. I fried an old power supply by blowing air into the fan and having the fan turn fast without power to cause it to turn made it react like a generator and feed power back into the PSU frying it…

    To be safe I recommend sticking a pen ir other small object into the fan to keep it from moving when you clean one.

  4. Groff

    I always use my Air-Compressor for the desktop. I wish there was an easy way to clean laptops. I will actually use a Vacuum on my laptop, but only to pull dust out of the heat-sink fins, and only for split seconds at a time, never had an issue with it.

    Million dollar idea: A hinge locked in place by two screws on the bottom of a laptop, un-fasten the screws and the heat-sink fins can be lowered and cleaned easily.

    …If only.

  5. Ryan

    I’m in need of cleaning my laptop fan seeing as I haven’t done it on the 5 or so years I have had my laptop. I ordered a can of compressed air the other day, just waiting for it to get here.

    Has the HTG done an article on cleaning your computer? If not it would be an extremely useful article :)

  6. Stewart Redback

    I have literally cleaned hundreds of PCs with a vacuum cleaner and never had any trouble.

  7. infmom

    Here’s a vacuum cleaner attachment that doesn’t generate static. Or at least it never has for me.,7651.html

  8. Andrew James

    That Synergy Program is great!
    I’ve used it to link my laptop and desktop computer. Fantastic.

  9. sneakily1

    While Synergy is a fantastic tool, let’s not forget Input Director… another great free alternative for using one keyboard an mouse on multiple systems over LAN.

  10. James Moore

    I use an upright house vac with a hose attached to clean out the computers I service. Never had a problem in five years. Always keep the hose touching the metal case to prevent static.
    I also advise my customers to use a good “cloth” filter in the AC to prevent fine dust in the air. The cheap fiberglass type only pass dust through.

  11. Ryan

    I’ve killed a couple of PCs at work using compressor to blow out the systems. This was maybe 8 years ago and I’ve since learned not to do that. Granted, this was a very power compressor used for air powered tools….probably created a huge amount of static electricity.

  12. rp

    Why not just copy the pdf to the kindle? Works for me on my DX.

  13. nadeendra

    If vacuum cleaning is not a good thing what happens I just use the blower ??

  14. Skip

    If you are going to use an air compressor for cleaning computers, dial down the pressure to 30psi. Even then, you’ll need to hold the fans still by inserting a tool through them. Full pressure can over-speed a fan and ruin it or blow a blade off in seconds. If you can’t stop the fan from turning, such as on a laptop or power supply, make quick passes pausing in-between to let the fan spin down .

  15. Andrew James

    At my company we have a air compressor that we use to blow out all the old dusty machines with. The air compressor is set to a safe level, so we don’t have to worry about damaging the computers.

    I’ve only been working at my company for a little over a year, but I can tell you. That a good blast out can not only save your computer from future damage. But bring what in some cases were falsely believed to be dead computers, Back to life.

    I say computers in general should be at least blown out once a year.

  16. zeeko

    Synergy is just beyond amazing .

  17. mark

    I heard the “Computer America Guy” (don’t know his name) tells people to use a leaf blower to clean PC’s?
    Pretty strange, never heard the show its not on the radio where I live.

  18. Anon

    I would never speak of a vac near my pc components. I use the compressor in my garage. I try to keep the moisture to a minimum by emptying it on a dry day then let it compress, then valve if any valve out what moisture has been created at the bottom valve and hose stone like filter valve. And set PSI to 15 or 10 and stand the nozzle a good aways, common sense, test the psi against the palm of your hand, if your hand moves, the psi is to high. All common sense.

  19. gary

    Was that computer actually that dusty or was it just set up as an example? Also how old is it? It looks like a p2 setup or earlier

  20. Carlos Ferrari

    I might be wrong but compressed air also has some oil in it, right?

  21. IBEW47

    using a vacuum is safe IF you use the blower end and not the sucking end – and use of the mini tool kit as noted earlier lowers the velocity and volume of the air stream to more than safe levels – it also does not have moisture issues like can air or a compressor does –

  22. Ian

    I had a customer who blew up a PC by vacuuming it and using the nylon brush attachment all over the motherboard. Fried the whole lot.

  23. JohnRobertM

    I’ve vacuumed tons of computers without ever having a problem. As long as you are careful, you shouldn’t have a problem. The company I work for is an industrial sized greenhouse. In our production HQ we have two huge dirt mixers that generate tons of dust. The computers over there usually require a good cleaning every six months or so. Another helpful hint for cleaning the decorative, plastic covers on the front is a dishwasher on the rinse / quick clean cycle (avoid cycles that heat the water).

  24. Andrei

    Thanks for the tip… I used to us the vacuum cleaner. Question: is the pic from the left (with that thick layer of dust) real?

  25. GranPaSmurf

    Synergy, now Synergy Plus, is a great tool, I have used it for years. Once you use it for even a few minutes, you will not want to be without it.

  26. Ron

    hairdryer on warm/low seems to work for me

  27. Brian

    It’s a good idea to hold smaller fans (processor fans especially), I’ve had to replace a few after cleaning out with a compressor. And pay special attention to the power supply for computers in bad environments, they can have a lot of build up.

  28. Andrew

    I am in agreement with Stewart Redback. I also have vacuumed untold numbers of computers without any ill effects. It is not clear to me how moving air can cause static damage, whether it comes from the suction of a vacuum cleaner or from compressed air.

  29. Larry

    Absolutely find a way to prevent your FANS from spinning before blowing air or vacuuming air. I have turned my quiet computer into something that sounds like a helicopter by ruining fans this way.

  30. Liz

    I have to add to the cleaning the computer with a vacuum cleaner, I have been doing it for years, with no damage. The chances are that if you leave the dust it will do more damage. I fix computers daily an do this, not once has anything ever been damaged. You are in fact right about all you said, however a quick blow won’t destroy your PC.

  31. Kurt

    Static is generated by the moving of the air, so it doesn’t matter if it’s sucking or blowing the risk is the same. The only “safe” way to do it is with ionized air.

  32. LH

    Most bigger compressors, not only pump out a lot of water vapour, they also pump out oil. So unless you have good filters inline, don’t use them. There are good, cheap, handheld ones available these days, that do an excellent job.

  33. Desolace

    ****Note; If you have a tank compressor, moisture can actually condense and accumulate in tanks especially when not used for a while. This can provide more than enough moisture to cause serious problems, and can even pick up ions from the inside of an uncared-for tank.

    Making a few blasts of air first, before turning the stream on the tender innards of your machine, should dissipate most of the residual moisture and keep any “camel-spit” incidents from occurring.

  34. Juan

    “lightening-strike” ? Enlighten me, please!

  35. SKC

    After showing numerous glitches at various times, I have take my old PC up to the local garage and blown hell out of it with their air hoses. Should be little static around the bowsers? Just avoid losing little bits such as ram etc into the oil soaked ground. Best to remove Ram, GPU etc first.
    I have kept an aging PC running well by doing this 3 times now over 6 years and each time it runs like new again, even though the problem, as recommended by an “honest” tech, was that I definately needed a new motherboard! (He seemed not to notice the dust, cobwebs and dead ghekos!)

  36. Deck Hazen

    I’ve also used a vacuum cleaner on my gear for many years without damage, but I use a small nozzle that reduces the air flow and supplement that with a couple of new soft-bristled paint brushes of varying sizes to loosen the stubborn bits.

    – Deck

  37. Penny Fuller

    How about prevention? If I use a cloth to cover the CPU, it might generate static electricity too. I think I would also have to uncover it when in use. How about using a filter for a vacuum–is there an intake somewhere that would work on?

  38. Max

    Your advice is well intentioned and most of what you say is good practical advice. A physicist will tell you that THERE’S ABSOLUTELY NO DIFFERENCE BETWEEN BLOWN AIR AND SUCKED AIR when it comes to generating static electricity. The drier the air the more the amount of static produced, so from that point of view sucking room air (has some moisture) through the machine probably has the edge on blown air which often has its water vapour removed. Whether you choose to blow or suck the dust away (a) ground the machine, (b) keep the nozzle out of the case and (c) suck/blow gently. The more powerfult the blower/sucker the further away you should start. Move gently towards the case until the dust comes out. Remember – there is ALWAYS dust present, even if you can’t see it with the naked eye. So don’t be obsessive and try to get every speck out. A little dust won’t do harm.

  39. Bill

    @ nadeendra

    ‘If vacuum cleaning is not a good thing what happens I just use the blower ??’

    I have a small Sop Vac. I have cleaned my room PC two or three times in the 3 years since I built it. I have cleaned our house Computer once, using a regular house vacuum with a hose attachment (allowing fans to spin, and not taking any special precautions to ground either computer) Did I just get lucky?
    After reading this I was wondering about using my small shop vac as a blower, but after reading further comments (esp. by MAX) I am questioning whether to do this too? It is time to do some spring cleaning and our household Computer is in need of swapping out the Optical drive, you know kill two birds with one stone, I just don’t want to kill the computer too.

  40. Ricardo

    I just purchased the Metro Data Vacuum (not a vacuum but rather used to blow air only) and it works great. Unlike a compressor this does not create/blow moisture and no worries about static electricity. It also includes different a few different kind of nozzles for reaching hard spots. For about $50 this is a great replacement to compressed cans.

  41. Charley

    I was just thinking of using a vacuum cleaner on my machine. Would it make any difference if the nozzle/attachments were plastic?

  42. actinium

    @Kindle books: Although Calibre’s library management is nice, but (by the same developer) is much faster than Calibre if all you need is to convert an ePub/PDF/LIT to mobi.

  43. JJ Rock

    I’ve vacuumed pc’s at least 20X since the 90’s -& I never had a problem. The first time I heard the “Do Not Vacuum” story – I figured it was some sort of CYA warning. Again – Never a problem, and I don’t know anyone who has had a problem vacuuming a PC.
    On the other hand – a dust clogged processor or power pack has to be one of the biggest reasons for PC problems. I’ll keep vacuuming – I think It’s much more dangerous NOT TO VACUUM it. (who has the time to disconect it, and open it up)

  44. Anon

    @Carlos Ferrari
    Some compressors might, for my compressor does not as it is a 2-stage oil free pump.

    Good statement, check your compressor see if it camel-spits out oil before attempting to use a compressor on pc components. Moisture prevention has been mentioned above.

    Glad I work on my own PC’s, not taking them to PPL that are recommending to use vacuums on their pc components and stating that there isn’t a problem with it. I could imagine a first time builder reading this, vacuums his six thousand dollar pc and ruins it by one little instance of static or hits a capacitor with the vacuum nozzle-brush [insert-face-palm-here].

  45. D. Davis

    Common plastic is one of the worst Electrostatic Discharge (ESD) materials there is. Air moving through common plastic tubes can cause the plastic to gather large amounts of Electrostatic Charge on the surface of the plastic. This large charge can cause damage to Electronic components that are sensitive to ESD. Actually, the Charge can be disippated from the plastic Tube in one of two ways. Either by the tube touching a PC Board which is loaded with tiny Printed Circuit Chips or if the charge is large enough, to jump aross the gap as the end of the tube is placed near the PC Chips (All of those tiny black sauare things on the Printed Cirtcuit board. The circuits in thses tiny chips are so small that an ESD Charge which can not be seen or felt by a human can destroy the circuitry in the Chip.
    Thus, the common plastic nozzle/attachments are the most dangerous ESD meanice.
    As to my qualification with regard to ESD matters, I was in charge of a comprehensieve ESD Protection Program (at an Aero Space Company in Austin TX) to delete / minimize the chance of ESD charges being placed on the ESD sensitive Chips.
    Yes I know that it appears that all of those chips have plastic stuff” near them. I will not go into that now, except to sy they are less of a threat because they are not coming from outside.
    If you are going to use small brushes be fore worned. Only use a brush that has a wooden handle and the NATURAL Bristles. That is, no Plastic handles and not synthetic/plastic bristles.

  46. D Core

    I have a small compressor in which I have purchased a water and oil seperator and plug it inline. I also use a secondary pressure valve to reduce the pressure to 20psi. they both cost about $10 each.

  47. Will

    I found Synergy to do a good job, but for joining just windows machines together I would recommend InputDirector. This will let you send unlock commands and other keyboard shorcuts to the clients or slaves as ID refers to them as. It also enables you to encrypt your traffic between the devices. Give it a look its freaking awesome.

  48. Mike

    I’ve been using my shop air compressor to clean PC boxes for years with nary a hitch! Never stuck anything in the fans, common sense says don’t allow the air to spin them up to a million RPM. Or blast 120 psi from an inch away. But then again……

  49. D Core

    I forgot to add that vacuums and leaf blowers can build a serious charge. The spark you see or feel can be any where from 15kv to 30kv or more. it’s a short burst but significant Some people I am sure remember dragging their feet to build a charge to zap your bud or what happened to me is I would pet my dog and give him a jolt unwillingly

  50. Andrew

    The proof of the pudding is in the eating, Max and Anon. I have done it many times and no problems have resulted. Not one single solitary customer complaint. Nuff said.

  51. Anon

    @D Core

    LMAO, reminds me of this family guy episode.

    Peter: (After shocking Chris.) What the hell was that? (Shocks Chris again.) Oh my God, Lois, don’t get alarmed, but, I think I might be Jesus. I’m Jesus.
    Brian: Peter, that’s a static shock. Your pajamas created a charge of electricity when you dragged your feet across the carpet and when you touched Chris, you passed it on.
    Peter: Kneel before Christ! (Gets up, rubs feet on carpet, shocks Brian.)

  52. Anonymous

    To Omnicontrol in Omaha,

    Why not just settle on one box, one host operating system (OS), and then run the other OS’s virtually? In this case, I’d go with Ubuntu as the host OS, install something like Oracle’s VBox (which is also free) and then run Windows and any other OS’s virtually! And with 2 (or more) monitors it’s almost begging for it!

    So forget Synergy unless you just have to incorporate another separate box (another real PC) into the equation for some reason. The only limitation might be your (one) systems RAM. But isn’t installing more RAM cheaper than adding an entire PC and then paying the power company to keep it on?

    It would seem to me to be a waste of energy to power up 2 PC’s burning up more fossil fuels when you really might only need one slightly more powerful PC with the right OS and software.

    …Just sayin’.

  53. Tom Walker

    To Ryan who ordered a can of compressed air and is waiting for it to come in. WTF! Where the hell do you live?
    To others that say using an air compressor to blow the dust out of a computer works for them. WTF! Where the hell do you live…in a rock quarry?
    Ron. Watch the hair dryer idea! Warm air can make the wire coating brittle. Make sure the airflow is cool.
    To the rest of you people: suck the moisture from your mouth & tongue by sucking air into your lungs. Now…here is the tricky part: purse your lips as if you were about to whistle…now blow out hard (not so hard as you nearly pass out!). Does this give you any ideas?

  54. D Core

    @ Anon

    Yeah. our poor dog. We moved into this old home to an area where the air is very dry. The old carpets where wool and we had this old paper wallpaper. It got to the point that kids dog and I were getting shocked even by touching the wallpaper. again the poor dog got to the point that he would avoid us.

  55. D Core

    Thanks for reminding me about blowing air on the fans. Luckily I had dismantled my motherboard before blowing air on the fans. That can cause a problem

  56. NFP1026

    I’ve been vacuuming my computers every six months since my original Leading Edge Model D from 1985. That’s a lot of computers and a lot of vacuuming and I never had a problem.

    If moving air is the issue with static charge, what difference does it make which direction it’s moving in?

  57. D Core

    Not to get all techy. A charge can be positive or negative , but that is relative. Correct me if I am wrong but most of us think that lightning strikes the ground. most lightning shoots upward while some do hit the ground. But you don’t want to be in either path. I don’t think it matters suction or blowing,it’s all about the potential (voltage) which way does it choose to jump.and how big a charge. but a charge is still a charge. I do not believe that direction matters.

  58. TheBigOldDog

    Not all ESD damage is immediately catastrophic. Much of it causes damage that is not detected immediately but over time, shortens the life of the components and/or causes intermittent failures that are difficult to trace. This is all well known and well document in the semiconductor industry and I’m sure you’ll find 1,000,000 articles trough Google that will explain this. So, when it comes to ESD you play it as safe as possible, There’s a whole profession built around ESD mitigation for a reason.

  59. Mike

    Hi, just to let all of you know I have been using a leaf blower from Toro for the past 5 years. This cost me less than $50.00 at home depot. Anyways here in South Florida I have a few maintenance agreements with some customers and every two-three months I blow out the dust. It really does the job but in reality dust is insidious and so you cant really get 100% out but I get out so much 90%+ that it really stays clean.

    For the rest I cant blow out I went to CVS and bought a fat makeup brush to remove the rest as
    best as I could. Like I said 100% no but high 90% yes.I always do this outside of course and since the force of the air is strong I place in a level area and sometimes next to a wall so the PC wont tip over. I start several feet off but get close in quickly. I clean the back first, then the side with the case open and then the front. I do this for up to 5 minutes sometimes a bit more. Once I am done I can really see the difference.

    I have seen memory that had dust ‘caked’ on and this helped a lot as well as the brush because caked on is very stiff. I have taken to wear a mask sometimes because some can get blown back
    towards me and they do say this computer dust can be toxic.

    Sorry this have been long but I do wholeheartedly recommend a leaf blower. It works great in my experience. I must also say I get close to the fans and they spin wickedly fast but never in the 5 years doing this have the broken. Perhaps I have been lucky.

    Hope this helps

  60. Andrew

    @BigOldDog: Still not convinced. How much is their life shortened? If it were truly significant, solid evidence would be everywhere and no one would be arguing about it here. It is not as clear as the evidence for dropping a rock on your foot, is it. There is also a huge industry that swears blind smoking doesn’t cause lung cancer. The argument “50,000 flies can’t be wrong” won’t wash, since humans will believe anything and anything can be argued.

  61. Nuwan

    With regarding the cleaning part, I’ll always use a paint brush of 1″ width.
    It’s really easy and harmless. Why use a blower or vacuum ?

  62. kaycek

    Please, no toothbrushes or makeup brushes! They have the potential to create static electricity and short circuit all of the tiny parts. Not only that, they also could actually knock a small wire off the motherboard, which would then give someone fits!

    If you are going to blow out the PSU fan, I recommend that you either turn the system on and do it, or that you make sure the fan is turning the same way it would if the system were to be turned on. I thought the leaf blower was an interesting idea, not ever having used a leaf blower even on leaves, I would think though that it would send too much air flowing through the system because of the force it would need to push leaves.

    I have found that by keeping any CPU off the floor at least a foot and a half there is less dust inside the case.

  63. DJRosen

    Turn the computer upside down. The unwanted dust will collect at top.
    Or sideways, so dust collects somewhere else.
    Port some of the drives external.
    Create a carriage with a second set of duplicate drives offline, so you can switch as the first wear out.
    Automatic backups set for a week prior.
    Create a password pattern based on the Kabbalah & date for password records.

    Freeze the Senior Tech in Liquid Nitrogen for future use.
    Thaw when future problems arise.

  64. b-man

    i vaccummed outover 300 pc’s at a school i was working in and not one failed with a static charge.. just vacumm out your computer and stop being a sissy

  65. Jswitz

    Compressed air WILL contain more concentrated H2O than the surrounding air (pV=nRT). When you compress air, the temperature decreases. If you compress the air until the temperature drops below the dew point, it “rains” inside the tank. Unless you live in a desert, being concerned about moisture in a compressor is far from paranoid. A relatively small tank can easily contain a cup of water.
    Yes, moving air causes static electricity. Air molecules are in friction with the molecules of the items they pass. This occurs regardless of the “direction” of the air. Air moves differently around a given device (eg. hose orifice) when it is expanding than it does when it is contraction (blowing vs. vacuum), but the end result is essentially the same: static electricity, of some magnitude. The amount of static electricity depends on the speed of the air (linear speed & turbulence), and the materials involved. Static electricity will dissipate differently depending on the relative conductivity of the material structure. As mentioned, emptying compressor tanks, limiting air speed/volume, grounding and fan protection are always wise precautions.

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