and I don't think there's all that much copper in "copper pennies" anymore -- is there?
from livescience.com:
"In 1962, the cent's tin content, which was quite small, was removed. That made the metal composition of the cent 95 percent copper and 5 percent zinc.
The alloy remained 95 percent copper and 5 percent zinc until 1982, when the composition was changed to 97.5 percent zinc and 2.5 percent copper (copper-plated zinc). Cents of both compositions appeared in that year."
Apparently we need to change our thinking to "zinc pennies"
