This is total zombie apocalypse stuff. Let’s say the world’s ending, there’s no more electricity and you need a knife. But all you’ve got are a roll of aluminum foil, a source of open flame and some unpowered hand tools. What do you do?
Admittedly, not all of you are going to have the sharpening media lying around, unless you’re knife nuts or hand tool woodworkers. But the fact that this is possible at all beggars belief.