Make is easy on yourself and just use DBAN or KillDisk, that should do the trick. Or have more fun with it, and treat it like the printer in Office Space. I personally like to remove the HDDs and smash them with a hammer, but most of that is because I think it's fun; unless you have sensitive data on your drives, I don't know that physical destruction is really necessary. Some agencies actually use industrial shredders to physically destroy the disks, so I like to claim that I'm doing everyone a favor by busting them up by hand. :)
Answer
Make is easy on yourself and just use DBAN or KillDisk, that should do the trick. Or have more fun with it, and treat it like the printer in Office Space. I personally like to remove the HDDs and smash them with a hammer, but most of that is because I think it's fun; unless you have sensitive data on your drives, I don't know that physical destruction is really necessary. Some agencies actually use industrial shredders to physically destroy the disks, so I like to claim that I'm doing everyone a favor by busting them up by hand. :)