If the marking on the molds is sharpie, isopropyl alcohol should get
it off. If ballpoint, try lighter fluid. (Be sparing with that. It
will go after the molds if left in contact.)
As far as organization: I’d do it by kind (ring/pendant/whatzits)
and then probably just a serial number. So “Ring 1, Ring 2”, etc.
Then shoot and cast one of each, to see if the mold still shoots, if
it shoots with reasonable effort, and if it shoots something you
actually want to make.
Then take a picture of the casting, and use that as your catalog
image. You can junk the casting (or not) after that. Your call.
Best of luck,