I would not recommend microwaving a hard drive, you'd only wind up damaging the microwave more than the hard drive. Didn't mom and dad teach you the repercussions about putting metal in a microwave and turning it on?
Wipe the drive clean if possible (and I don't mean with a towel ... lol) , Drill holes in it then smash it into a million little pieces with a sledgehammer of your choice , recovery after that is 100% impossible.