My teen has a half dozen of the classic MASTER combination locks which
I'd like to re-use for my PE for my grade schooler, yet the teen doesn't
remember the combination to any of the padlocks.

They're the classic colored-dial Master combination locks.
They're all locked but not locked to anything.
There is no serial number that I can see.
It just says "Hardened" on the hasp.

Is there a method for finding the combination?