Also, if you blast the fans so that they turn while you are blowing it out with the canned air, it will also clean your fans. Goes for the one in the back, just point the canned air from the inside out on the fan in the back and you will see the dust fly out the back. Never blow outside in, kind of defeating the purpose, lol. I have been doing that for ages and it always works, especially if you start hearing noise from your tower. I try not to keep mine on the floor, but sometimes space is a problem, so you get alot of dust from the floor.