How do I destroy a hard disk?
If you are looking for standard procedures and reliable methods, you could read the Guidelines for Media Sanitization (PDF) of the National Institute of Standards and Technology.
For any given medium, there are three basic methods:
- Clear
- Purge
- Physical Destruction
For hard drives they recommend:
Clear:
Overwrite media by using agency-approved and validated overwriting technologies/methods/tools.
Physical Destruction:
- Disintegrate
- Shred
- Pulverize
- Incinerate: incinerate hard disk drives by burning the hard disk drives in a licensed incinerator.
Purge:
- Purge using Secure Erase. The Secure Erase software can be downloaded from the University of California, San Diego (UCSD) CMRR site.
- Purge hard disk drives by either purging the hard disk drive in an NSA/CSS-approved automatic degausser or by disassembling the hard disk drive and purging the enclosed platters with an NSA/CSS-approved degaussing wand.
- Purge media by using agency-approved and validated purge technologies/tools.
Recommendations for flash media (SSDs) are similar, except that degaussing solid state drives is not a viable way to purge them as the data is not stored on magnetic platters.
Thermite is the Ultimate Solution. (To both data erasure and many other problems)
It shouldn't be that hard to expose the platter after peeling back the various stickers covered in dire warnings. Once exposed, you have a choice of fun methods. Bending it even a little would make spinning it under a head impractical, so that is probably a good place to start. A ball peen hammer could be used to make a nice texture, or just apply a belt sander. Wear eye protection, naturally.
Pragmatically, unless you are holding national secrets, just scoring the platter with a scratch awl really ought to be sufficient to make it well beyond anything but the NSA's capability. If you are really worried, score both radially and in spiral.
Hand the wreckage (or at least the bits you don't hang up as a trophy) over to an E-Waste recycler and they will do something appropriate with it.
A combination of really strong magnets and a sledgehammer is really the only way. In that order.
See if your company already employs a bonded security firm for shredding documents. I use ours for shredding reports, digital media, old backup tapes, and hard disks. IIRC, it costs two bucks per hard disk, and they grind 'em to powder. No fuss, no bother, no eco-issues.