I picked up a couple nice commems today, including a nice Bridgeport and a 1921 Pilgrim commemorative. I paid full Greysheet on it, it was that nice. But it had a ton of die polish, which to the untrained eye looks like someone cleaned the coin. Does anyone know which coins tend to have the most die polish issues? Thanks.
There really isn't an answer to that question. And the reason there isn't an answer is because die polish lines are specific to a specific set of dies and as a general rule every coin was minted with many different sets of dies. So you can find coins from almost any series, in any denomination, with prominent die polish lines. There are exceptions of course, but not that many.
I was speaking with Kleinman once about a Type II $20 Liberty that was mintstate that I thought had way too many marks and problems to be in a minstate holder. He explained how the mint workers would swab out the dies and how debris often came out in the process of minting coins as a sort of bas relief. The graders know all this and do not downgrade for natural process. Are there any videos pre-1933 of the minting of all the various coins showing how the mint workers did their job?
There is a grain of truth in that explanation, but only a grain ! For the most part it merely provides a a convenient excuse for the TPG to over-grade the coin. It goes hand in hand with things like roll friction, flip rub, weak strike, even cabinet friction. But the topper of all toppers is when PCGS says that all, repeat all, Saints have luster breaks (rub, friction, wear) except the counterfeits ! No. There is that one from roughly that time period that shows some coins being minted, but it doesn't show enough that you can actually see anything.
