And it is not that hard or you need a forge. My dad would make blades out of worn out or broken hacksaw blades to use around his printing shop and I got cut more than once with the suckers. Here is an example of somebody’s damn good-looking blade via a hacksaw.
The other thing that can get sharpened? Credit/Debit/Gift cards. I had never given it a thought till I saw a Burt Reynolds movie where he was a private detective in Las Vegas but only carried blades and kept his credit cards razor-sharp as some sort of surprise weapon.
This is an ad for a sharpener, but it shows a gift card sharpened enough that I believe will inflict sever damage on a human. Think neck.
And if you really want to see creativity, hit YouTube for videos on how to make prison shivs and the like. Let me put it this way: I will never see a Sharpie with innocence ever again.