i prefer air compressor myself if you have one great just go low on the psi i usually run 100-150 and don't get very close motherboard or cars, i clean the case and everythign liek this once a month and my system has been running great for 3 and a half years
You are playing with fire doing it like that g00f. Unless you have a dehydrator inline with your aircompressor, you are introducing moisture to your GPU. If the smallest amount of moisture stays on your card when you plug it in, poof you just lost your card.
I would rather play it safe and use canned air. If that isnt enough air pressure put the can in a bucket of HOT water for a few mins, that will give the can a good bit more PSI.