The U.S. Mint at one time produced many regularly circulated coins that were composed of 90 percent silver. In the 1960s, silver prices rose sharply, making the precious metal in the coins worth more than the face value of the currency. The government in 1965 changed the composition of the coins, reducing the amount of silver used in minting them. Many older silver coins are no longer in circulation, but if you know how to identify them, you might just find one.
Check the date on the front of the coin. The last year the U.S. Mint made true silver coins was 1964. Most coins minted in 1964 and before have 90 percent silver content; coins minted since 1965 have far less silver content and are not considered silver coins.
Determine what denomination of coin you have. All dimes, quarters, half dollars and dollar coins from 1964 or earlier are 90 percent silver.
Examine the rim of the coin if you cannot read the year in which it was minted. If the rim is solidly silver colored, it is a silver coin. If you see a brown line running along the rim, it is not a silver coin.
Examine the back of any nickels minted between 1942 and 1945. Because of the need for the metal nickel during World War II, the government removed the nickel from the coin and minted nickels with 35 percent silver instead. Look for a large mint mark -- a P, D or S -- above Monticello on the back side of the coin to determine if you have what is known as a "silver war nickel."