A.Gent wrote:

Don't forget saw blades. My appetite for high carbon steel is well-fed by
salvaging broken power hacksaw blades and cold cut-off saw blades.

I'll add old circular saw blades. These have been kicking around our
place for years. Nowadays I'm using carbide tipped circular saw blades
for all my woodwork. A couple years ago I saw a magazine article on
cabinet scrapers and decided I'd like to try one. I cut a piece about
4" square out of an blade with my plasma cutter, rough dressed the edges
on the bench grinder and finished it up with diamond hones. I made a
burring tool from a piece of drill rod and now have a good scraper.

Ted