Cleaning a computer system fan, whether it is a CPU fan, case fan, or power supply fan, requires some care and the right product. Below, are the steps and suggestions for cleaning the fans within your computer to help keep your computer running cool and efficiently.
Caution: While inside the computer, make sure it's off and that you're familiar with ElectroStatic Discharge (ESD) and its potential dangers.
Caution: When cleaning a PC fan, it is best to make sure the fins of the fan do not spin. Keep the fins in place while using canned air or the vacuum/duster. This helps prevent damage to the fan and make it easier to remove the dust from the fan.

Clean fans with compressed air

Compressed air canFirst option for cleaning computer fans, or any computer part in general, is by using canned air designed for electronics. This type of canned air is designed to be static free, helping prevent damage to computer components. Using canned air made for cleaning electronics is the safest approach, as well as the cheapest.
Tip: When using compressed air try to position the computer in a way that helps the dust and dirt escape the computer and not just move somewhere else in the case.

Clean with electronic vacuum

The second option is using a small electronic vacuum or electronic duster. These devices are designed to reduce the chance of static generation or discharge, helping protect electronics like canned air for electronics.
Caution: Use caution when using a vacuum that plugs into the wall. These vacuums generate ESD, which could damage your computer. Whenever using these types of vacuums, remove the fan from the computer.

Damp cloth

If the computer you're working on is in around a smoker, the fan may look like the picture shown in the picture on this page. In this situation, it's usually best to moisten a cloth with water and rub the fan down. We also highly recommend removing the fan from the computer when using a damp cloth.

Steps in cleaning

Once you've decided what you're going to use to clean the fans open the computer case and locate the fan you want to clean. In most situations, you're going to need to remove the fan so that both sides of the fan can be cleaned. If the CPU fan is connected on top of a passive heat sink, it must be removed to access the dust on both sides of the fan and dust in the passive heat sink.
Once the fan has been disconnected from the computer holding the fins of the fan in place with your fingers or placing your finger in-between the blades either blow the dust away using the compressed air or suck up any dust using an electronic vacuum.