I weigh all of my 1982 pennies. If it is over 3 grams; it's copper. If it 2.5 grams; it is a copper coated slab of zinc.
I take this stuff seriously.
Of course, I don't take it seriously enough to write down the weights. I am either showing a bunch of copper pennies or a bunch of zinc pennies.
I thought about buying some of those plastic containers that hold 50 pennies. I decided against it because the store asked for more than 50 cents for the container.
Anyway, I weighed all of my 1982 pennies ... dagnabbit.