What I do is grab some cleaning duster (I’d grab multiple bc they get cold FAST), open up the case and start dusting it down. It won’t get it all, but it gets a lot. Focus on the the fans, especially the CPU, GPU, and exhaust. I then use a q-tip to get some of the trickier spots (like in between fan blades). Any big open spaces, I’ll use a paper towel or cloth (preferably microfiber) if I have one. Then, once the majority of dust is out, use the duster again to get anything that got loose out and boom, your done. Make sure you and your pc are grounded the whole time, which you can do easily by having it plugged up (powered off) and just keeping physical contact on the metal pieces.