Silverware is a common find at flea markets and garage sales. The important thing you need to determine is if the silverware you are looking at is pure silver. What is commonly called pure silver is really sterling silver. Sterling silver is 92.5 percent silver by weight and 7.5 percent by weight of another metal or alloy. Silverware would not be made of 100 percent silver because it would be too soft to use. It is combined with an alloy to make it strong and functional. You want to make sure the silverware you are purchasing at the flea market is sterling and not just inexpensive silver-plated flatware.
Look for a mark on the silverware of 925, STERLING or 925/1000. The mark is usually found on the underside of the piece of flatware. One of these marks is a surefire way to tell if your flatware is made of sterling silver.
Put a magnet on the silverware to see if it is attracted to it. A magnet will not be attracted to pure silver flatware, only steel and other metals. If the magnet is not attracted to the silverware, there is a good chance it is sterling silver.
Wipe the silver with a silver polish cloth gently as if you were trying to clean it. If your silverware is made from pure sterling silver you should see black tarnish rub off on the cloth. Pure silver is subject to oxidation just from being exposed to the air. Steel and other metals will not tarnish in this way.
Look for a mark on the silverware such as a crown, crest or lion. Sterling silver from countries outside of the United States often has a mark as opposed to STERLING or 925. The marks can be small and hard to see, especially if the piece is worn. A maker’s mark is a fair indicator your piece is pure silver especially if your piece is not attracted to a magnet and black tarnish rubs off on a polishing cloth.