It's useful for blasting dust, crumbs, and other crap off your keyboard and electronics, but those overpriced compressed air cans are almost as big a rip-off as printer ink. So here's a brilliant and relatively simple hack that makes a compressed air can refillable with a standard tire pump. And just to highlight what's probably the most crucial step in this project: you'll want to make sure the can you're using is completely and thoroughly empty before going at it with a drill, be aware of the can's recommended PSI before filling it, and just be careful when attempting this. [YouTube via Dooby Brain]