While compressed air is the best way to clean your CPU fan and all other hard-to-reach areas in your computer case, it can damage sensitive components, if you’re not careful. This is because the high-pressure stream of air can dislodge small components like RAM modules and graphics cards. It can also blow dust and debris into areas you can’t see, which can lead to long-term damage.  To use it properly, do not spray for more than a few seconds at a time to avoid the freezing moisture in the compressor. Hold the can upright, 12 inches or 30 CM away from the surface you’re cleaning. Move it around evenly to cover all areas.  Make sure to use short bursts of air rather than one long stream. By doing it this way, you won’t damage your PC at all.