Anyone know a decent cordless battery powered hand vacuum for getting dust out of a tower. I don't want to use one of those compressed air cans that just blow air around into even darker harder to reach sections of the tower. But I also don't want to use a vacuum that is to powerful. So far the voltages I am aware of are 4.8V, 7.2V, and 15.6V. Preferably a vacuum I can buy from common electronics store like circuit city or best buy. Thanks in advance.