During 1943, the height of the second world war, copper was in such demand for the war effort that pennies were briefly made out of steel. They probably should never have gone back to copper, because exactly 40 years later in 1982 the price of copper and the value of a penny crossed paths again, and they had to switch to zinc, for good this time.
Steel pennies are actually zinc-plated steel, just like cheap roof flashing, and they corrode the same way.
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 20 September, 2002
Text Updated: 18 December, 2007
Sample Group: Coins