Valuable coins go in and out of people’s wallets more than you’d think—many people don’t know what collectable coins to look for or may not even think about the fact that some coins have more value than what’s printed on them. That’s why it’s important to read up on valuable coins so you can know if you’ve come across one before you just give it away. Here are some valuable coins that could be hiding in your pocket change:

1. 1970-S Small Date Lincoln Cent With a Doubled Die Obverse
This small error turned a coin with a $0.01 value to a $3,500 treasure. This 1970 cent has doubled lettering in the words “Liberty” and “In God We Trust”—if your coins letters are doubled, . What’s more, there’s a version of this coin that has a small date in the numerals, so if the 7 in your coins “1970” is level with the rest of the numbers, it is of the small date variety that is more rare.

2. 2004-D Wisconsin State Quarter With an Extra Leaf
If you have a 2004 Wisconsin state quarter, look out for this printing error that could get you $100. On the back of the coin, a cow, a wheel of cheese, and a cob of corn are featured—the deformity is in the corn husk. If your coin has an extra leaf on the left side of the bottom of the corn cob, you have a rare coin on your hands.

3. 1999 Wide AM Reverse Lincoln Cent
In 1999, the U.S. Mint produced two types of Lincoln Cents with subtle deformities that made them worth between $45-$530, depending on the condition. To check if your coin is valuable, on the reverse side, the AM in America will either be so close that the letters are touching or set wider apart than normal, with the latter being more rare.

4. 1982 No Mint Mark Roosevelt Dime
Every coin has a mint mark of “P” for coins made in Philadelphia, “D” for coins made in Denver, and “S” for coins made in San Francisco. Coins that were distributed with no mint mark are often more valuable, in particular the 1982 Roosevelt dime that was produced without the “P” mint mark. This coin is typically worth about $100 when it’s in decent condition.

5. 2005-D Speared Bison Jefferson Nickel
The Jefferson nickel has a buffalo on the reverse side, and if you have one from 2005, be sure to check for this deformity that makes it worth more than $0.05. If the buffalo on your nickel has a speared line down the middle, you may be able to get upwards of $1,000 for the minting error.

6. 2005-P “In God We Rust” Kansas State Quarter
Another minting error resulting in the typical statement “In God We Trust” becoming “In God We Rust” has made this 25-cent coin worth an extra $100. If you have a quarter minted in 2005 in Philadelphia, make sure you check for the missing T.