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Go to your local computer store, BestBuy, CompUSA, CircuitCity, or anyplace that sells electronics for that matter, and buy a can of compressed air.

This is the safest way for cleaning out all of that dust. However, it does make a big mess (stirring the dust in the air). Anyway, just spray the dust off your computer parts, and if you notice a little frost buildup on some parts don't worry it evaporates quickly.
 
Do clean it ones in a while (the dust could get your fans stuck).
I use a simple hoover ('ne stofzuiger' as they say here) for the job.

There are sprays for cleaning the packs of dust out of cracks or from a print plate, here my procrastination jumps in.

Cheers
 
I, too, recommend compressed air. I've been using 'Dust-Off' by Falcon, which I got from Fry's. It seems to work very well with no frost.

Good Luck,

scem0
 
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