In the US, pennies were copper until 1982 (except for 1943 when they were made from steel due to a wartime copper shortage). Now they’re made of zinc. Pre-1982 pennies have a melt value of 1.8 cents today. I save any that I find, but it’s fewer and fewer every year as “bad money chases out good.”
I bought some Canadian silver coins from 2013 to 2015 today. They are all 8 dollar coins, but some are 1.5 ounces and some are 1.25 ounces. That’s confusing :-)