Every now and then I clean my machine, not too often though. I find that a can of compressed air works best.
Easiest way to manage dust on radiators is to run a pull configuration on the radiator. Dust builds up on the side of the rad air comes from, so in a pull setup dust builds up on bare radiator rather than underneath a fan. From there you can just brush it off with your hand.
Or if you mean "clean out" as in internally, a warm 20/80 mix of White Vinegar and Distilled Water should do the trick. Pour it in, cover the ports and shake it around, rinse and your good to go.
@Astralav
Typically top and rear mounted fans are exhausts, so manufacturers don't put dust filter's on them as it would only inhibit dust leaving the case. You typically put filters on intake fans.
Not to belittle your A+ Certification, but there's just some stuff your not going to learn from a book :lol:.