This is a very fortuitous thread! I have a lot of older marbles that I would like to clean up for my display purposes only, but have wondered about the ethos behind the whole thing. Lots of polished marbles being sold as original finish, which is downright wrong, but I am sure happens a lot. I have some good ones with just enough small problems to detract from the meant beauty of the dang things. I am getting the vibes that it is okay to polish your collection as needed, but it should absolutely be documented so that future inheritees know the history behind the marble. And I am sure no one in this forum would ever, knowingly sell a polished marble without all kinds of disclaimers, right?
Thank you for these great posts that are loaded with good stuff!