Collectors and dealers determine the value of old U.S. coins using factors such as grade or condition, rarity, age, bullion or melt value, and historical significance. Other factors include the popularity of particular types of coins and dealer inventory in specific areas.
One of the most important factors in assessing the value of coins is their grade according to the Shelton Scale, with 70 being a perfect grade. Uncirculated coins stored in sealed tamper-proof containers are most valuable, while coins with scratches and other imperfections, dull luster, and weak strikes receive lower grades. Some coins are rare in good condition but plentiful in poor condition, while others have absolute rarity because few were initially minted or few escaped removal from circulation and subsequent melting for metal recovery. Coins of absolute rarity with few remaining copies are good investments, because they continually appreciate in value.
Not all old U.S. coins have high value unless they are also rare and of good grade, as some are plentiful on the market and of poor quality. Some coins have higher value as bullion than as collectors' items. For instance, poorly-graded silver coins dated before 1965 are valuable for their silver content. Occasionally, coins have particular value because of their unique history. For instance, genuine U.S. silver dollars marked 1804 were actually minted in 1834 as gifts to the king of Siam, whereas the silver dollars that were minted in 1804 are marked 1803.