any magnet will do as long as you get it next to the nerve paths. i like the magnets in old hard drives. they are small and very high gauss. the very best use of a microwave(dear god, please tell me you dont use a microwave for ANYTHING) is to dismantle that suc*** and steal the magnets from the magnetron. they are very strong and fairly large. they are donut shaped like speaker magnets(another source but not as powerful). they will pinch a blister on you. there are two in there. they are positive on one side and negative on the other. dont get a compass too close to them or they will ruin it. they will also ruin floppy discs, cassette tapes, VHS, and possibly other electronics. slowly move a compass toward one side of the magnet. as soon as the needle points to the magnet dont get it any closer. note which needle and back off. if it was the north needle that pointed at it then that side is negative. if the south points to it, its positive on that side. always use the negative side toward your body unless you learn more about using magnets medically. its a fairly easy learn, but for another time.