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Cheap Bulk Eraser for Hard Disks?
cute-boy asks: "Recently I had to replace some hard disk drives from the same batch which had failed, while still under warranty. Because the drives were no longer recognized by the SCSI controller, it was not possible to erase the data on them. In view of the sensitivity of the data contained upon them, and the chance this was still forensically recoverable, our company decided to buy new drives rather than risk the disclosure of their contents by returning then to the supplier. How would you non-destructively (physically) destroy data on a hard disk without access to a bulk eraser? Obviously in this case it's a bit late to be thinking of using encryption."
Make friends with someone who has access to a tire shredder. The shredder will make quick work of the drive and you can then burn the remains for added security or pass them directly to a local recycler (most cities frown upon throwing computer materials in the trash as they usually contain heavy metals). Another option would involve fun with thermite but, that may involve a bit more risk than you are willing to take.
The most painful way, but only sure way to accomplish this is to disassemble the drive and melt the platters. If they are really old drives, then waving the disassembled platters under a wand-based degausser usually works. This stuff is all measured in oersteds. The recording head has to overcome the coercivity of the magnetic media in order to record a reliable signal. Coercivity is the strength of magnetic field (measured in, you guessed it, oersteds) required to alter the alignment of the particles on the platter. The heads can write at this strength and so must you if you wish to properly erase the data. That's why the big bulk erasers cost so much. The big one, the TD-1 can do up to about 8000 oersteds, which will do anything up to, but not including the perpendicular recording stuff in the 500+GB drives.
If you're a cheap skate, you and a T-8 wrench are going to be friends (get a bit for about every 20 drives cause they wear out fast if you're in a hurry) and pull the drives completely apart, down to getting the platters off the spindle motor. Some drives take a T-10 or T-6. Then send the platters to be burned. If you don't courier them to the incinerator, then at least play 52 card pickup with them and make it difficult for any but the most determined.
Go to the local park one day when they're trimming the trees. Just take all of the HDDs and throw them into the big chipper/shreader thing that they have there. Voila, no more HDDs to worry about.