Self Destructing Drive

Okay I recently managed to get a few hard drives, what I really have been wanting to do is make a self dustructing drive. I have done some thinking about it, and I would perfef if the ammount of damage done was limited to the drive its self, so no gun powder or thermite. I was condering somthing like a electro mag that I could put inside the drive case to wipe the bastard.

So anyone have any suggestions?

Use an external hard drive and keep it in a microwave oven on your desk.