Like a lot of people who have been using computers for over a decade, I have performed "upgrades" more times than I care to remember. Among the more mundane of these upgrades have been replacing hard drives -- sometimes because they failed, but mostly because they eventually were filled to capacity. I'm kind of a pack rat, and this leads to problems in real life spaces, because when paper, books, and magazines accumulate, they occupy space which ought to be available for humans -- a situation guaranteed to get worse over time. The only options are either throwing things away, or moving to a larger space. Both options are problematic, for obvious reasons.

However, thanks to the continuous evolution in computer technology, I've never had this pack rat problem with hard drive space. It has been expanding and expanding almost infinitely in a way that reminds me of the movement outward of the Universe since the Big Bang. Hard drives get bigger and cheaper, and by the time I've "outgrown" one, there will be one that holds five times as much on sale for a fraction of the price I paid for the filled-up drive.

Because hard drives are fairly small in terms of physical size, the old ones haven't been a big problem; they just sit around gathering dust. But I am stuck with them, and because they contain passwords, financial data, over a decade of old email, and a daily stream of personal consciousness more detailed than any diary could ever be, they're not things I'm willing to just pitch in the trash.

From an economic standpoint, even if I could scrub and reformat them safely (more on that in a second), I cannot sell or even give them away. Old hard drives of 10 Gigabytes or less are useless and worthless, because they're too small for modern purposes. I actually have a 750 Megabyte hard drive if you can believe they ever made such a thing, but physically, it's identical in size to my latest 320 Gigabyte drive.

A lot of people think you can just reformat these things and throw them away. Wrong, wrong, wrong. If you want to be really paranoid, even using the best DoD approved techniques which involve multiple random overwrites of 0s and 1s do not scrub the data sufficiently.

I was shocked to read that the government does not want you to know that:

The second problem with official data destruction standards is that the information in them may be partially inaccurate in an attempt to fool opposing intelligence agencies (which is probably why a great many guidelines on sanitizing media are classified). By deliberately under-stating the requirements for media sanitization in publicly-available guides, intelligence agencies can preserve their information-gathering capabilities while at the same time protecting their own data using classified techniques.

Sorry, but no one messes with my palimpsestuous images, pal.

The only genuinely secure, safe and foolproof way to delete data is by physical destruction of the drive itself. Not just putting it out of its misery with a sledge hammer, because the plates are still inside and some sneaky bastard could theoretically still come along, put them inside another drive, and scan them with his killer microscope. You have to destroy the platters.

If you go to all the trouble of taking one of the silly drives apart (careful, as they're vacuum-sealed and go POOF!), and dissecting the hell out of it, you'll find these:

(As you can see, I've got too much on my platter.)

I think dissolving them in strong acid or reducing them to powder with a bench grinder ought to satisfactorily take care of the problem. But let's face it, that's a hell of a lot of work. I poked around a little bit, and learned that degaussing is the next best thing, but hard drive degaussers are expensive.

What about powerful magnets? The military has developed a hand-crankable box (the "Guard Dog") containing neodymium iron-boron magnets which is supposed to render any hard drive totally useless in a matter of a few seconds.

While they don't sell these things, four inch neodynamium magnets with a 750 lb, pull are available for sale here, and they're described as dangerous:

They are incredibly powerful and should only be purchased by users familiar with the proper handling of large neodymium magnets. Two of these stuck together are virtually impossible to separate by hand. They can pinch and cause physical harm if they are not handled with extreme care and respect. You must read and understand our Neodymium Magnet Safety Page before ordering these magnets. You must also agree to our Terms and Conditions prior to purchasing. THESE ARE DANGEROUS!

But would it work? Might the gummint geeks still be able to get at your palimpsestuous images with their scanning tunneling microscope recovery techniques? I don't know, but I still like the grinder.

I did find another enjoyable method which would appear to be foolproof, and that is called Drive Slagging:

We finally decided that the only sure way to thwart data recovery was to melt down all the aluminum contained in the platters. Slagging the drive would have two effects on the medium. First off it would convert it from a readable disk to any shape we decided to pour it into. Secondly it would nullify the magnetic properties of the coated aluminum.

What's left is guaranteed unrecoverable.

And who said meltdowns can't be enjoyable?