Heads up, Rielle Hunter: Next time you try to destroy a sex tape, you'll want to burn, crush, or shred it: The one-time paramour of John Edwards reportedly tried to keep their video private by pulling the tape out the MiniDV cassette—which was found and restored by Andrew Young (who then watched it with his wife). The most surefire method would have been to incinerate it, explains Jessica Dweck for Slate, but if she wanted to hang on to the tape for memory's sake, a degausser would have done the trick.
The instrument alters a tape's magnetic domains, making it permanently unreadable. Unfortunately, government-certified degaussers cost thousands. Nonmagnetic storage media like DVDs should be burned—again, the best and simplest option, writes Dweck—or run through a shredder. But don't do it at the office. To prevent the DVD from being restored, the particles can't be more than 5 millimeters in length; only expensive micro-cut shredders cut them down to that size.