Roamy here. Mr. RFH brought me a page from his fact-a-day calendar that said,
To conserve copper during World War II, the United States produced zinc-coated steel pennies. The copper saved was enough to meet the combined needs of 2 cruisers, 2 destroyers, 1,243 Flying Fortresses, 120 field guns and 120 howitzers, or enough for 1.25 million ammunition shells.
This was done in 1943. There are a few rare 1943 copper pennies out there that used up the blanks left over from 1942. The zinc-coated steel pennies were a bust – people confused them for dimes. The zinc coating didn’t cover the edges, so the coins started rusting. One of the articles I read on this said that vending machines were set up to catch steel slugs as counterfeits, so the pennies didn’t work. I’d like to ask our older readers if vending machines actually took pennies back then. Maybe they meant slot machines.
In 1944, the US Mint went back to normal-looking pennies that were made mostly out of recycled brass from shell casings. They continued this for 1945 and 1946. These coins have aged darker than coins from other years.
Another interesting fact? There were no dollar coins in the US minted between 1935 and 1971.