What is "altered surfaces" ?

sinin1

I have had copper coins come back in a bodybag for "altered surfaces" - can this happen on any type of metal and what is the usual cause (what does it mean) ?

homerunhall

The most typical form of "altered surfaces" we see is "thumbing." The doctor will take a coin, say a Morgan dollar, and rub substances on the face to cover marks. Substances can be anything, even nose grease, i.e. body oil from the side of your nose. Another form of AS we see is when the coin has a "shammed" look, i.e. a really unnatural rubbed-up look to the surfaces.

Tilt your coin under an incandescent light and look for weirdness in the surfaces.