I like what I did. If anything defaced the chip, it is the cigarette burn. Removing some of the burn from one small portion of the chip along with one millionth of the clay is hardly tampering with history.

I have to laugh that some jerk burning a part of the chip years ago (which destroys, let's say, one thousandth of the chip) is viewed as history worth preserving. Maybe my removing some of the burn and destroying another one millionth of the chip will be viewed years from now as part of the same sainted history.

I remember now when I did these dastardly deeds:
(1) a while back I bought some hundreds of inlaid common clay poker chips at a flea market. I joked with the dealer, and told him he could leave them out, and if he sold them for more, we could split the profit. They did not sell, and they got baked some in the sun. So at home I used the Scotch Brite (or whatever it is called) to clean the "sun tan" off.; and
(2) I once bought boxes of Embajador, Santo Domingo, Dominican Republic, chips that had bottoms to the boxes, but no tops, so the people who packed them used cellophane tape all over the top to hold the chips in place. I used the Scotch Brite (?) there to help remove the tape.

Perhaps I never used them on casino chip burns, but it seems like a good idea.