I remember back in 1965 when the first clad coins were introduced, one of the major concerns was that eventually, as the top layers wore down, the pure copper core would show up and cause undesirable situations to develop such as rapid oxidation, etc. Now, nearly 40 years later I have yet to see even one clad coin that has worn through to its copper core. I do understand how hard the nickel/copper mix on the outside layers are and that it does hold up for a very long time, but IMO I feel that we will be seeing the copper core on many clad coins soon. Wonder what others think.
No, it won't happen. The rims and top of the portrait are where the clad layer is thinnest on most worn coins and almost all of these are less than half way through. There will be the rare piece where you can see a little copper on the rim and others have claimed to see it on the portrait but at least the former are likely anomalies caused by striking, upsetting, wear, and/ or cladding differences. These coins have to wear nearly smooth for much copper to show and at the rate they are wearing virtually all will be lost or destroyed first. In thirty years it may not be so unusual to see a little copper on them but it will not be typical or common.
The only copper I usually see on clads is on the rims of the Kennedy halves and Washington quarters. But it's only really bad on the Kennedys.
