The 1943 steel penny was a special U.S. one-cent coin created during World War II. To save copper for military needs like ammunition, the usual bronze penny was temporarily replaced with one made of steel coated in zinc. This made the 1943 penny magnetic and lighter. Although over a billion were made, people didn't like them much, often mistaking them for dimes and finding they rusted easily. The U.S. Mint went back to copper in 1944. While most 1943 steel pennies are common today, a few very rare and valuable ones were accidentally made using copper instead of steel. You can tell these rare copper pennies apart because they are not magnetic.
