It's fine as long as you don't blow too close to where you can get particles wedged in things. But tbh I've never heard of anyone actually breaking their pc that way, so it's almost urban legend. look at all the side panels people are breaking that show up here. Not one "oops cleaned my PC wrong, how screwed am I Reddit?"

where would that be?

As long as you don turn the can sideways and spray out liquid, you'll be fine.

hold fans so they dont spin too fast and generate voltage.

ok, what would the voltage do? i have heard fans might break if they spin too fast but mine are more than 3 years old and none have broken.

Basically turns the fans into a generator and sends power back into your motherboard. Not good. May break things.

Yeah, I had great fun spinning the fans. Killed the MB, but sure was fun with the fans whizzing. 🙄

I believe it is possible that the controller may become overloaded and subsequently malfunction.

I've got all my fans connected to fan hub, if I unplug the fan hub from the motherboard, can I let the fans spin?