Re DVD shredding: Do you have a power drill? (How about safety goggles?)
I recently decided I didn't need a bunch of DVD+R backups I'd made about 4-6 years ago, so I took a drill to them! Had them all on a cakebox spindle, held them down with a thick-gloved hand, and the bit went right in. Not only do I imagine that the rough edges and missing chunk would make it really challenging for anyone to get data off it, but the vibration / torque seemed to separate the layers on most of them, leaving the dye layer exposed to the elements. Took only about 10 minutes to do a stack of 50 discs, and that included setup and clean-up.
(If you try this, please be careful!)