I just raced out to the workshop to see if mine was still there. I thought you may have stollen it. It looks just like that.
Agh! It's using a chisel or punch that gets them boogered up so you can't use a proper tool, like you made David, to remove them. The right tool for the right job. I learned that I can still do a backward somersault when I was yanking on the breaker bar to remove a stubborn cam nut and it suddenly came loose.
Using the right tool is all fine and good when one is at home in the shop, but when one is on the side of the road or some other out of the way place "ya use what ya got" AKA known as improvising.
The Army Official nomenclature for that process is a "field expedient"