... papper wrapper roll will know that after 50-70 years there are deposits that come to the surface.
Whenever someone asks me why I didn't rebuy a Floridian "50" Casino chip when listed for $150 or $200, I mention that I've seen examples that have been cleaned to remove the rubbed (chip against chip) marks... and want no part of it. I've also mentioned that the rack marks being removed from a slighly used chip is a dead givaway that it has been cleaned... Thus my few remaining Floridian "50" chips are still selling (last 9 examples) at the $300 level because they have never been touched by anyone after rolled at the factory.. not even by the person I got them from (except me, of course)... to remove them from the original paper roll.

That's not to say what my buying/maintaining/selling practice is better than the next guy's, but you seem to interpret it that way.

JB