I bought an 1803 large cent off of
ebay. When it arrived, I took it out of the cardboard flip to examine it with a magnifying glass. It felt real grainny and on the obverse side, it had a real small area that looks a bit like clean pitted copper under the surface. I took a small bit of never dull wading to rub on a small part of the edge, it does not clean up like copper but a brownish color comes off instead.....any idea's?