I feel for you... I just dug my first really old coin from a travel way that the revolutionary troops used. Im dealing with the same problem. I have enough lettering to ID it but at this time its just not readable. Its soaking now in hot peroxide but so far I havnt seen much if any change. I didnt know that the excitement of finding this coin could lead to depression so fast. I feel that I will never find another coin this old. Im going to put it under a microscope and see if it helps detailing the letters.. If that dosent work I will probably still keep cleanning it until there's nothing left.
What kind of coin is it? Liberty nickel? Indianhead?
I would put it in olive oil for a while and see what happens. Olive oil won't hurt the coin and it is a preservative that will help lubricate the metal.
hey, EZ whats to lose. i got a large cookin' now in h2o2. it's my first dance but 2 hours and double dip and i can see a face. heat the perox. when it cools and it will keep cooking for some time. let me know. Bill. it's only a penny!