[header] How to clean a cpu fan [title] Shut down your pc and turn the power off. [step] Remove the power cords from the rear of the tower and disconnect them from their power source. [title] Place the tower on top of an anti-static mat that has been laid on top of a table. 
[step] You may also wear an antistatic wristband that is connected to an electrical ground, like a metal plumbing fixture. You'll need to use the antistatic devices because static discharge from the floor or from your body could damage data stored on the computer.