How to Dust a Computer

by JoHarrington

The grills on your PC let out the heat, but they also attract dust and dirt. Too much of that and everything will grind to a halt.

I had a fortuitous moment earlier today; and I have Wizzley to thank for it.

I was writing an article about Speccy, when it occurred to me to actually open the program and check my own PC's performance. Careful, conscientious people would do that every day; but who's got time for that, when there's Reddit to read?

It's probably been a good couple of months since I was anywhere near Speccy. Hence I hadn't noticed how my computer's core temperature was starting to creep up.

What I read in there was enough to make me abandon my article immediately and get out my trusty PC dust tools. Though naturally I took pictures along the way to teach you how to dust your computer.

Computers Filled With Dust and Grime

If you think they look riffy in the picture, you should have seen them in real life!
Image:  Two dusty computers waiting to be cleaned.
Image: Two dusty computers waiting to be cleaned.

Why Do You Need to Dust Your Computer?

It starts with your PC slowing down. Ignore the dirt for long enough and components begin to break.

When I was young and naive, I never cleaned the hardware inside my PC tower. I didn't even know to do it and, if I had, I'd have been scared away by the strip across the seal. It warns that you will void your warranty by going inside.

That's your own fault for taking out warranty.  Since when did any of those usefully pay out?  And the alternative could be voiding your computer instead.

For years, I blithely surfed the internet and messed around with my files, innocently unaware that behind the casing things were going wrong.  Dirt and dust were creeping in through the vents and settling upon my motherboard.  Whole tangles of them were clogging up the fan.

I didn't even know when the fan cracked right across and stopped working. 

The first I knew of anything was when I was getting the blue screen of death at least once an hour.  The second major clue was when I burnt my finger on the top of my computer tower. 

After I was finally persuaded to bravely unscrew the casing and look inside, I couldn't believe my eyes. Huge dust-balls sat everywhere I looked.  I didn't even see the cracked fan at first. I couldn't find the fan. It was encased in grime.

I was grimly informed by a geek to thank the Gods of the Internet for the fact that all computers crash when they over-heat. It gives them chance to cool down.  If they didn't, then eventually it would have ended in flames.

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What Can Happen If Dust Builds Up in your PC?

THE END OF THE WORLD! By which I mean that you might be without the internet, while your computer is fixed.
  • The computer slows down a little bit more each day, as resources are diverted into maintaining stability. Meanwhile, dust is accumulating on the memory nodes, which does make it difficult for the computer to recall what precisely you were attempting to open.
  • Components become sluggish. For example, it might take several attempts to read a disk or DVD. That will be the optical drive lens unable to transmit its laser beam through the dust balls.
  • Programs take a while to open or refuse point blank to do so. Error messages abound.
  • There could be a chugging noise, which grows gradually louder each day.  This is probably the fan struggling to turn.
  • The area around your Power Supply Unit (PSU) is always warm. This is normal. What isn't normal is when it's hot to the touch (hence that burnt finger). It's unable to pass heat through the grime towards the grills.
  • There is a perceptible amount of heat coming from your computer's vents. The fan can't cool the air inside, either because it's now broken or the dust is wadded around it. (There's a heat-sink beneath the fan, which can also get blocked.)
  • Components begin to over-heat.  By now you will be having the blue screen of death, if you're lucky.  If it's really bad, your computer won't bother with such niceties. It'll cut straight to 'off' and you will be staring at a blank screen.
  • Components begin to fracture or fry.  The former occurs when they've expanded in the heat further than their capacity to cope. The latter is when moisture in the air has been soaked up by the dust, which isn't great in an electrical environment. You end up with rogue currents.

It's not really worth going on, because it's unlikely that your computer will stay on long enough for much else to happen.  You will certainly be off buying new parts or taking your PC into a repair shop. 

The first thing that technician is going to do is open the case, stare at the dirt and privately judge your slovenly housekeeping. But you're keeping that person in business by not cleaning inside your PC, so they'll be happy to let you get on with it!

What Happens When You Overheat the Central Processing Unit?

Tom's Hardware demonstrates with various CPU chip-sets. He's removed the heat-sink completely. If yours is clogged with dust, it might as well not be there either.

Preparing to Clean Inside Your Computer

Please read this bit, there's health and safety information within.

None of the above happened to me today, because Speccy had headed it all off at the pass. The software had informed me that my PC was getting a bit hot, before any problems had begun to manifest.

However, I might have over-stated how quickly I grabbed my dust-busting tools.  In reality, I did the laundry and a bit of washing up, then generally tidied up.  None of this was important to the job in hand, but for one major fact - I was killing time.

You cannot dust inside your computer while it's still warm.  Wait half an hour after switching it off, before you open up the back.

There are two reasons.  The first is that the PSU will be hot and you might hurt yourself.  The second is that you're exposing the inside to the open atmosphere without the protection of the casing.  There's moisture in the air.  There's electronics inside.

This will naturally be the longest half an hour of your life, but when it's finally over find something metal and touch it.  Not the PC!  This is solely to earth yourself, just in case you're carrying static electricity. 

Now, if you haven't already, take out all of the cables from the back of your computer tower.  The power cable should be self-explanatory.  You shouldn't be inside your PC while it's still plugged into the wall.  That way leads to electric shocks and hospitals.

The rest (head-phones, microphone, webcam, memory sticks, keyboard, mouse etc) is simply because you're not staying at your desk.  You and your computer tower are heading outside!

Things You Will Need to Dust Inside a Computer

A Phillips head screwdriver to open up the back; and compressed air dusters to blast the dust away.

Opening your Computer Case

Unscrew the screws and slide it back. Simple!
Image: Opening a PC case with a screwdriver
Image: Opening a PC case with a screw...
Image: Sliding back a PC case to open it.
Image: Sliding back a PC case to open...

If you have never been inside a computer tower before, then it might be a little nerve-wracking.

Don't let yourself be intimidated.  Everything within is held tightly or bolted into place. Unless you're planning on being rough with it, there's very little that you can do to break it. Even if something did come out, it will be apparent where to put it back.

There will be two or three screws holding the lid down.  Find them and employ your Phillips head screwdriver to remove them. 

The laws of the universe state that you will lose one of these screws by the time it comes to replace them.  I thwart such an inevitability by having a little pot ready to drop them into. It's worked so far.

Once the lid is loose, lay your hand on it and pull away from the front of the tower.  All standard models slide out like this.

How to Open a Desktop Computer Case/Tower

Dusting Inside Your PC With Compressed Air

This is absolutely the recommended method of cleaning a computer's hardware.

We can't use a normal duster and a can of polish inside a PC, because that would involve liquid and rubbing.  Both would damage your motherboard. 

Instead the recommendation is to use compressed air.  This blows the dust out, rather than wiping it off. The air comes out at a terrific speed!

A third reason, why you have to wait half an hour for your computer to cool, is that oxygen and heat aren't a great combination either.  Probably nothing would happen, but why take the risk? Obviously don't do this next to a bonfire, lit barbecue nor any other naked flames.  If you smoke, put your cigarette out before you start squirting. 

This is done outside, so that you aren't using pressurized air in a confined space.  Plus it saves on extra housework, as you haven't just blown dust-balls all over your living room.

And incidentally, it's so much fun to do!  What's not to love about aiming a nozzle, pressing a button and seeing dust just disappear in front of you? 

Image: Cleaning inside a computer with compressed air.
Image: Cleaning inside a computer with compressed air.

All you have to do is aim the nozzle away from you and blast away at the dust. Try to chase any dirt-balls outside of the casing.  We don't want them left inside.

Pay particular attention to the fan, and the metallic box that it is attached to (the heat-sink).  If your fan is tiny, then it might be worth sticking a pen or pencil into the blades first.  That will stop it going around when the compressed air hits it.  The pressure from that can might be faster than the little fan can cope with!

As long as the fan is clean, it can sort out the rest of the hardware.  But you might as well clean everything, while you're in there.

Once it's clean and shining, pop the case back on.  Tighten the screws back in and congratulate yourself on a job well done.

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Confession Time....

The astute amongst you will have looked in deep suspicion at the photograph of me dusting a computer with compressed air.

For a start the PC looks remarkably clean already; and secondly, the can is totally different from any of the compressed air canisters shown.  That's because it's really a can of VDU cleaner, strategically held so you can't see the tell-tale name.

But don't be put off by that.  The scenario and the way it's being positioned are all perfectly correct for compressed air.  It illustrates the method well enough, even if it was faked.

Let me reiterate again that the steps already described are totally the correct and recommended way of cleaning a computer. 

But rules are meant to be broken, right?  Follow me into the rest of this guide for a demonstration on how I (and at least three I.T. repair shop technicians and another four geeks of my acquaintance) do it instead.

Things You Will Need to Clean a Computer My Way

You only need the one Phillips screwdriver, but it's a nice set! Plus a pastry brush and a vacuum cleaner with a plastic nozzle.

Why Else Would You Buy a Pastry Brush?!

Image: Preparing to dust inside a computer.
Image: Preparing to dust inside a computer.

Cleaning PC Dust With a Pastry Brush

Warning: This method isn't nearly as entertaining as the compressed air. It's more like proper housework than barely disguised playing.

I use the pastry brush and vacuum cleaner method mostly because it's cheaper than buying compressed air canisters.  You can reuse these.

I'm also confident about working with what's inside the computer, so I'm not worried about breaking anything.  If you are nervous about messing with a motherboard, then do go ahead and follow the recommended method instead.

However, my way is very easy, if you want to give it a try.

After opening up the casing, as was already described, step one is to stare in horror at all that dust. 

Image: Very dusty computer!
Image: Very dusty computer!

For the record, you are looking at two different computers here.  I was being nice and doing them all. 

The second one is much dirtier than the first.  There are four likely reasons for this, which may help you prevent your own from gathering so much dust!

  • Computer one isn't switched on as often as computer two.  Frequent use means that more air is circulating, hence more dust getting in.
  • Computer one is properly positioned on the desk.  Both PCs sit off the floor.  The higher you can place your tower, the less dust it will attract.  Even an inch or two will make a difference.  But computer two is mine, hence it's forever having memory sticks and such being moved in and out of its rear USB sockets.  I've lazily got it sideways on for easy access - by both myself and the dust.
  • Computer one is in a room which is regularly vacuumed and polished.  If there's less dust to get in, then there's less dust in there.  Computer two is in a room with a very ashamed occupant.
  • Computer one is owned by a non-smoker.  Unfortunately for the chain-smoking owner of computer two, it's not just dust that can get in.  Smoke stains the insides just as much as it's making the room's walls yellow.
Image:  Dusting a computer with a pastry brush.
Image: Dusting a computer with a pastry brush.

I used a brand new pastry brush for dusting out my computers this time.  I have a dedicated one for cleaning. 

It's not only that I don't want to baste my pastries with a brush that's swept gunk from a PC.  I also don't want to risk moisture from the washing up getting into my computer.

Don't use a brush with a metal handle, as that may build up static electricity.  Wood, plastic or silicone is best. It's also better not to use natural boar bristles (especially for the boar), as they have a tendency to shed hairs.  You don't want to just replace the dust with boar bristles!

Be vigilant, as you gently brush away at the dirt.  If you see a strand drop, then pick it out.

Concentrate again on the fan and the heat-sink beneath it, but don't be too worried about flicking dust from everything else too.  My pastry brush went over every nook and cranny in those PCs earlier, and I'm typing this article on one of them now.

Image: Using a plastic vacuum cleaner to dust a PC.
Image: Using a plastic vacuum cleaner to dust a PC.

I hesitated before including this next part of my computer dust cleaning method.  Things can, and do, go wrong here, so it comes with a few warnings.

Only use a vacuum cleaner with a plastic nozzle. A metal one will carry static electricity.  It does have the potential to direct an unexpected current, and that can damage your components. A plastic nozzle won't do this, if you use it correctly.

By 'correctly', I mean that you are not running this over a carpet here. Dragging your plastic nozzle over your motherboard will dislodge things.  They will snap off (and probably zoom off up the tube), thus breaking your computer.

My nozzle never actually touched a thing in there.  I hovered over the dust a few inches above. 

Also ensure that everything inside your computer is securely attached.  Your RAM probably won't be the same after it's been in the cleaner bag.  For this reason, you should never simply vacuum through the grills. You can't see what might be loose inside.

I only get the vacuum cleaner out if the PC is really dusty.  Computer one was spotless after I'd only applied the pastry brush.  Computer two needed that little bit extra.

Two Clean Computers!

After all of that, this is the finished result. Incidentally, Speccy recorded that my PC's core temperature had dropped by 40 degrees Fahrenheit afterwards.
Image: Computer one is dust-free!
Image: Computer one is dust-free!
Image: Computer two is sparkling clean!
Image: Computer two is sparkling clean!

More of my Geek Articles

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Updated: 03/09/2014, JoHarrington
Thank you! Would you like to post a comment now?


JoHarrington on 08/25/2012

is that what it is? All I know is that the canisters of compressed air are so much fun, when you're chasing those dust bunnies through your hard-drive. It's all, 'Come on, particle, make my day!' SQUIRT!

Thank you for your comment. :)

kingvixes on 08/25/2012

An air cleaner is basically a device that's used to remove contaminants/dust from the air. Also known as air purifiers they're installed in rooms that are constantly filling up with these minute solid particles

JoHarrington on 07/23/2012

Thanks, Sara. And good luck with cleaning out your desktop. Shout up if you need anything.

Sara on 07/23/2012

Well explained. Will look at this again when cleaning my old desktop. Thanks

JoHarrington on 07/01/2012


Worth considering, Jerrico?

Sam on 07/01/2012

Jerrico_Usher and JoHarrington,

You really should think about writing a few articles together - your humour matches ;-) SY

Jerrico_Usher on 06/30/2012

Awesome :) ... you said on the "case" haha Nice. (I'm always out for a good pun). Thanks!

JoHarrington on 06/30/2012

Awww, thanks Jerrico.

I'd be happy to do this, but I believe that fellow Wizzley author RyanUk is on the case. I'll check with him and if he's not, then I'll write one for you.

Jerrico_Usher on 06/30/2012

I hit the WZ like and nothing happened, I hit it again- nothing, waited a bit, hit it again and got a "thou shalt vote only once" but the number is still the same- I tried...

Jerrico_Usher on 06/30/2012

Hey Jo, I have a all in one HP Touchsmart- not so easy to dust this baby but I'm about to try, what say you do some research and write one for the all in one varieties (or laptops as they are made the same way only bigger :)

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