I used crazy glue once to get the piece out. Put the tiniest drop of glue on the piece in my hand and then put the key in the lock. Waited 10 minutes and pulled the entire key out.
I was told the best way was to use a thin fish hook. You straighten it out and when when you slide it in the key slot the barb will hook the rest of the key.
Have you ever been to a tractor auction? I noticed several guys who had big rings of keys. I guessed they were dealers. They could start any tractor on the lot. I guess one size fits all is pretty common in the tractor world. I got the spare keys for my Yanmar at the John Deere dealer. No cutting involved.