I agree with you, Fred. When I was a beginning collector, I used to clean all my used chips as well. Now I am very sorry! In addition to preserving the chip in the condition it was last played in, leaving the dirt on will someday significantly increase its value. I used to clean my used coins too back when I was a beginning collector in the 50s and 60s. Twenty years later when I tried to sell some of the better ones, I found that I could not get them graded and that dealers only wanted them for peanuts.

Enjoy the old history. Let the chips fall where they may, even they sometimes get dirty [g].

By the way, even Doug Saito will leave the chip dirty if you ask him to. Otherwise, he polishes all the history away and delivers sanitary chips that look like they were just made yesterday.