This is a very, very, old trick counterfeiters used to make their crude fakes look like circulated genuine pieces. The Chinese are using it in various forms. I first saw this type of surface alteration on ancients and world coins way back in the '70s. Many fakes were covered in a "black shoe polish-like" coating so only the relief details were visible. The image is a crude Chinese Large cent covered with black goop. The underlying coin was a bright, fresh, red copper when struck. It has toned down slightly to a more orange hue poking out of the goop. When you see a circulated copper coin with this sort of bright color it may be genuine or not BUT its surface is 100% not original.
It seems like the counterfeiters don't go for the Mint State copy, they go for an AU or circulated grade for the coin, costing less, but where buyers will be more forgiving. Would you agree with this, Insider ?
Yes. While using a stereomicroscope and knowing what a genuine US coin should look like makes detecting any Uncirculated counterfeit very easy so far. The problem comes with authenticating worn "problem" coins. Every major TPGS has slabbed this type of counterfeit in the past. Additionally, relying on outside consultants has proved to be very costly to at least one top service. It is lucky that when a coin leaves a TPGS, millions of eyes are waiting to find a mistake!
