They re-sell them (they only pay you a fraction of the value.)
Most coin dealers will do this for you.
Coin dealers will buy coins.
There are a number of dependent coin dealers throughout the US. Some popular companies are Liberty Coin Service, Springhill Coins and Heartland Coin Gallery.
Coin dealers and jewelers are known to buy coins.
Most coin dealers buy coins
Banks don't buy old coins, coin dealers will buy old coins, some jewelry stores will buy old coins, banks will take your old coins at face value and then sell them to coin dealers and and make some profit.
Coin dealers buy coins.
You might try Ali`i Coins in Honolulu
For pocket change a bank or credit union will exchange coin. If they are collectible US coins Florida has a lot of coin dealers.
One can learn about value of old coins on the website Coins About. Most coin value guides give you retail prices; that is, they tell you how much coin dealers are selling the coins for.
Online, Ebay. Or you could try the local coin shop, dealers often buy coins.
Jewelers and coin dealers usually buy gold and silver.