I've been reading about this issue on the net and nearly everywhere they use small air spray bottles which cost a lot... Can the fans be cleaned e.g. with cloth or a paintbrush?
How often should one clean the fans if one uses the computer for 3D modeling and video editing?
It doesn't matter what you use the computer for, there are only two factors for it:
1: How often it is on... 100% of the time? 50%? 10%?
2: How dirty your air is... a lot of dust? pet hair?
Air in a can is THE only good and easy way to clean it. If you have access to an air compressor (the good kind, with a storage tank, not a silly tire inflator), you can use that to blow the dust off instead of canned air.
Oh yeah... If you're feeling brave, you can do this:
1: Disconnect all power, and remove the CMOS battery from the motherboard.
2: Let computer sit for 1 day to make sure all capacitors are discharged.
3: Clean it off with a water hose.
4: Let the computer dry for 2 to 3 days.
5: Reconnect power and re-install the CMOS battery. Open the CMOS after booting up to put your settings back where they should be (they'll have reset to factory defaults).
It's fine to get a computer wet, as long as there is no electricity applied to it at the time.
The sad thing is that by the time most people think to clean system fans it is too late. the dust acts like an abrasive. Once the damage is done it is too late.
The good news is that most fans are relatively easy to replace. Some fans are easier to find than others but I haven't seen a truly proprietary fan on or in a computer for at least 10 years.
How long will one air compressor last? They are usually quite small and expensive... Can they be refilled somehow?
So cleaning the computer fans with a paintbrush or cloth is not a good thing???
How come? Is there the possibility that the fans might break or something?
I would see how the cloth works compared to the brush but I would supplement that with a little air.
I would check your fans after a month and see how it is doing. How often you need to clean the fans is a function of your environment.
Tap water contains salts that will be deposited on your hardware when the water vapourizes. Not a good idea.
For cleaning fans it's probably easier to remove them from the case and put them on a workbench (use a good lamp to properly see the dust). The plastic parts of the fan are not sensitive to electrostatic discharge (ESD) or water so they can be cleaned with e.g. a slightly wetted cloth.
In general for cleaning hardware (including PCB's) I wouldn't recommend a cloth due to ESD, but a small paintbrush will do. Make sure to ground yourself before touching your hardware. It's also handy to keep the tip of a working vacuum cleaner near (not on) the surface you're brushing - it's healthier and more efficient to remove the dust from the air instead of letting it spread around the room.
I think just use compressed air from an air compressor. You can normally hire from a hire shop.
every 2 weeks or so I un attach all of my connections and hul my cpu tower out to the garage and blow it out with high pressure air. I blow through all fans and opening both directions till I can't see anymore dust. Heat is the number one cause of electronic failures