Yes, but not on bronze. There is/was an odd light greenish tinge on the reverse, in artificial light, to a 1923 a/UNC shilling I bought in August 2009. Leastways it was visible for a time. When I just looked a few minutes ago it wasn't there ~ or didn't appear to be. Definitely not verd, but a overall slight hue. Lord knows what causes it. Greenish hue on silver? Are you sure it's not simply the result of past long-term storage in pvc coin album pages? If it is, acetone works wonders. I bought a bulk lot of Unc (recent) 2/6's and they originally had a bad green hue due to pvc storage...I will try the acetone trick to completely cure them.