>>https://www.youtube.com/shorts/JuhmeRPF09o
>>This reminds me: It's a good idea to use compressed air once in a while to blow dust out of computers and other equipment. If you do so, remember to hold fans still so they can't rotate while you blow them clear. In addition to ruining their bearings, oversped fans can generate enough back EMF to damage motherboards or other equipment they may be attached to.
>
>I've heard that the first rule of business is not to blow air while the motherboard is powered, because there's a good chance that the fan will start turning backwards, and then generate a current in the wrong direction, and that is what can cause damage. Besides, in most situations, blowing air through the exhaust holes doesn't do much, just distributes dust and fluff around. For a proper cleanup the fan needs to be taken out.

Usually it's best to work from within the computer case (can be challenging with laptops, some disassembly required). Fans can then be aired in their normal flow direction, and dust can escape.

If you have sticky particles in the air like cigarette smoke then yes, the only real option is to remove the fan completely to clean the blades.

>Oversped fan? What are these guys using, truck repair compressors?

Size doesn't matter ;) It's easy to overspeed even with just a can of "compressed air". Usually any pressure ~1 bar or more above ambient, released through a nozzle or valve, is supersonic: https://www.youtube.com/watch?v=DfYlLns0els

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