I actually just did that today. I don't have compressed air cans, but what I used was an air compresser (can be found at most auto shops) and just stuck a small nozzle on it and blew all the dust out. Also, one tip I will add is that if you run a fan on your video card (most geforce4's have em, along with newer radeon's) pull your video card out and blow the junk off that thing. Dust in a fan can sometimes gum up the bearings, causing a slower fan and less cool air on your GPU.