Dearborn, that is a very plausible explanation of the op's coin. Never would have though about that. It would have had to be a very tiny grate though due to the spacing of the lines but does make sense. Especially showing the discoloration on the rim and edge in the op's 4th pic as well as no discoloration on the lines that would have laid on the grate. Let's call it the "Seared Cent". Pretty neat find IMHO. These kind of posts make me want to experiment with coins. Very cool!