Originally Posted by InOmaha

Theoretically, if you had a CNC machine laying around, and the time or want to play with doing it, you could take a larger ring and machine it down to a smaller ring. You just need the CNC files. Doing it by hand would not be feasible, but people have weird hobbies so someone can spend there time on that if they want to file away.

Or toss the rings in the recycle bin and let someone make something else out of them.