To calculate the cost of junk silver, divide the face value of the coins by 1000 and then multiply the resulting fraction (decimal amount) by 715 to determine the number of ounces of silver present. Then multiply the number of ounces by the current spot price of silver to yield the dollar value of your junk silver. Remember that most dealers either add a small premium to the value when selling and subtract a small premium from the value when buying. A full bag is $1000.00 in face value and contains approx. 715.0 troy oz of pure silver. A half bag is $500.00 in face value and contains approx. 362.50 troy oz of pure silver. A 1/4 bag is $250.00 in face value and contains approx. 178.8 troy oz of pure silver. A 1/10 bag is $100.00 in face value and contains approx. 71.5 troy oz of pure silver. A roll of dimes face value is $5.00 and the silver content is 3.50 troy oz. A roll of quarters face value is $10.00 and the silver content is 7.00 troy oz. A roll of half-dollars face value is $10.00 and the silver content is 7.00 troy oz. 90% silver (junk silver) is the cheapest form of investment silver. The price is based solely upon the silver content of the coins. Fortunately, a given face value of any coin, whether a quarter or a dime, yields the same silver content. Because $100.00 face value in dimes contains the same silver content, 71.5 troy ounces, as $100.00 face value of half dollars or $100 face value of quarters, the calculation is the same for all denominations. U.S. coins minted prior to 1965 were composed of 90% silver and 10% copper. The main reason they are known as survival coins is the fact that they are legal tender coins. Also, because people remember when they circulated as money, they have the advantage of being easily recognized as money. If the need arises to use these coins in everyday transactions, Americans will feel comfortable accepting them as payment for goods and services. Additionally, because they are denominated in convenient amounts, they will work well in trade. A full bag contains $1,000 face value of dimes, quarters or half dollars. A bag of dimes contains 10,000 coins; a bag of quarters 4,000 coins; and a bag of half-dollars 2,000 coins. When minted, a $1,000 face value bag contains 723.4 ounces of silver. Due to wear, however, a bag of circulated coins yields approximately 715 troy ounces; therefore, to calculate a price, multiply the weight (715 troy oz.) by the spot price of silver. Different dealers use slightly different constants for this calculation. For example, thesilverXchange uses "715" as the constant whereas other dealers may use "712" or even "700".