You get them every time you make a cash purchase in eastern Iowa but before you toss 'em in a piggy bank or penny caddy at a convenience store, check to make sure you're not throwing away big money.

Modern day pennies are made almost entirely of zinc with a thin layer of copper. However, it hasn't always been that way. And that's where the magic could happen to your net worth.

In 1943, most pennies were made almost entirely of steel, because the U.S. needed copper for World War II. If you find a 1943 penny, put it to the magnet test. If it doesn't stick to a magnet, it's probably worth a whole lot of money. Why? Because each U.S. mint accidently produced 1943 pennies that were made of copper. They're rare and very valuable. The full description begins at the 2:58 mark of the video below:

That's not the only pennies worth big dollars. The video below shows 20 different pennies that are also valuable. The magical years are 1909 (two different versions), 1911, 1912, 1914 (two different versions), 1915, 1922, 1924, 1931, 1944, 1946, 1955, 1970, 1972, 1983, 1984, 1992, 1995, and 1999.

I'm checking my penny collection tonight and I'll take a second look at every one that goes through my hands from now on... how 'bout you?

[via Boing Boing]