I stopped using compressed air on dusty towers after a tech in Denver showed me what it does to the fans
I always thought blasting a case with canned air was the fastest way to clean it out until a buddy showed me last month how it just pushes dust deeper into the bearings and now my fans spin loud as heck. He held a flashlight behind a fan I'd just blown out and you could see a whole cloud of junk stuck in there, so now I pull the fans and wipe them by hand. What's your go-to for a nasty dusty rig, brush or vacuum?