[fdeee]

The only proper way of disposal is physical destruction, preferrably on site and under observation of inhouse staff. There are contractors you can hire in those: https://shredsupply.com/hard-drive-shredding-trucks/ (no relation, just arbitrary google hit).

I'm also unsure as to why you are getting drives back at all, any of your customers should not have any kinds of storage devices leave their site intact. At least that is the standard over here in Europe for healthcare and other industries dealing with sensitive data.

[bshipp]

Shredding/sledgehammer is likely the best option for secure disposal of mechanical drives, but SSDs are a different animal and are likely reusable given some of the suggestions in this thread.

[fdeee]

Not really. HDD recoverability is a myth, anything overwritten isn't coming back with modern HDDs. Bits can't "bleed out" anymore, density is far too high for that.

The thing you need to guard against is relocated/reserve sectors, in HDDs same as in SSDs. The proper way to do this is full disk encryption, and if that's not possible, physical destruction.

[hedora]

Most hard disks support hardware level encryption and full disk erase at this point.

There’s very little need to sledgehammer anything given realistic attacker models.

[fdeee]

Both, HDD/SSD encryption in hardware and secure erase have been proven untrustworthy numerous times.

[h506001]

Oh, we did stuff like this for disposal. The tricky part is drives we desired to recommission.