I've replaced too many fans where a gung-ho user has stripped the hub of blades using compressed air to ever consider suggesting shooting compressed air into a fan. Even if you don't strip the blades off, you're sending dust and fluff exactly where you don't want it to go [and where it won't get during normal operation] - back under the fan and into the hub.
Anovoca wrote:Also there is a chance that compressed air spins the fans and causes a back current into your machine. Risk is minimal but still present.
Aranarth wrote:You forgot one:
DO NOT SMOKE.
DPete27 wrote:There seems to be a lot of advanced suggestions for an OP that is seemingly a beginner