Wiping a Hard Drive

Question:
What is the best way to ensure that
nobody can recover any information from a hard drive that’s being
thrown away? The drive is very old; though it’s still operational, it
isn’t worth putting into a new computer or external enclosure. It holds
the OS and all files. I want to pull all documents and such, then
effectively wipe the drive clean and/or destroy it before throwing it
away.
—Greg R.
Answer: Wiping a Hard Drive