Thad, actually, I have seen several copper cents with this silvery sheen, and I believe it is due to how they were stored, as I mentioned above. In one case, the coins were wrapped in old tissue paper then placed in those little old yellow 2x2 envelopes (that contained a great deal of sulfur) for many many years. I bought several Lincoln cents from this collection and many of them had a beautiful iridescent silvery gray sheen to them. Sorry, that 26-S will have to remain entombed!
If you run across an inexpensive, raw one, please pick it up for me. I'll buy it and analyze it. Thanks