[Nil]

NIST Special Publication 800-88r1 covers this concept in excruciating detail

http://nvlpubs.nist.gov/nistpubs/Special...0-88r1.pdf

Bookmarked. Although I would like to see some proof of concept somewhere. Specifically studies and experiments done entirely on overwrite/clear methods on drives. I think that would be more useful than NIST guidelines that tell you to overwrite your hard drive, and overwrite it more to be safer. Of course that's simplified but it's still nothing we haven't heard before and doesn't do a great job of lowering our suspicions.