For years I have been using an autoclave floppy to securely delete my hard drives. Well, autoclave is no more but its creator is recommending another linux-on-floppy formatting disk known as Darik’s Boot and Nuke (aka DBAN.) The author of Autoclave has this to say about it:
DBAN has much better hardware support, better customization options, a better selection of erase methods, and a better user interface. It is better than Autoclave in all respects I can think of, and I say that as the author of Autoclave.
If that was not high praise enough, it should be pointed out that DBAN is used by the National Nuclear Security Administration to safely delete old hard drives.