That old coin you found in your grandfather's dresser drawer could be worth hundreds or even thousands of dollars. Most coins struck by the U.S. Mint before 1965 were 90 percent silver, making them highly collectible for both scarcity and metal content. The values of such coins are largely dependent on their condition. Most coins grade between the barely worn "uncirculated" (MS-63) to the well worn "fine" (F-12) and "good" (G-4). Coins in higher grades can fetch big premiums over coins that have seen lots of use.
Buy the most recent edition of a reliable price guide. Top guides for coin collectors include "Whitman's Red Book" and "The Official Black Book Price Guide." These contains pictures of coins as well as detailed descriptions of grades.
Examine the coin for contact marks. These are slight damages made to the coin by it coming into contact with other objects over the years.
Check the luster of the coin. If the coin has a bright shine as if it just came from the mint it will grade higher than a coin with a dull appearance.
Inspect the coin for wear. Because coins have different features, the spots on a coin that suffer the most wear will frequently differ. Generally, hair lines and the feathers of an eagle's breast are the first to disappear after a coin has been well circulated.
Grade the coin and look in the price guide to determine the fair value of the piece. Only coins with a nice luster, few contact marks and little to no wear can grade MS-63. Conversely, coins must be well worn to grade as low as G-8. Most coins in general circulation fall in the middle in such grades as "very fine" (VF-20) or "extremely fine" (EF-40).