AAK2 wrote:
You could also hold it on either end of the board and twist it back and forth until you hear the board start to pop (but not so much that it will remove the components). That should weaken the electrical contacts holding the components and chips on, making the data unrecoverable.
It is also quick and fairly easy to do, while keeping them intact.
That's a pretty good idea. It's probably the best thing to do, because if you did it that way, you could still get the Hard Drive Board grade for them.