Cast iron skillets have been in use for more than 2000 years, with some Chinese skillets dating to the second century B.C. Antique cast iron skillets vary in value depending on several factors, including the condition and rarity of the skillet. Collectible cast iron skillets must be usable, and skillets with extensive damage such as holes or missing handles are not collectible. Since cast iron has such a long life span, valuable old skillets can be found at yard sales and in thrift stores.
Clean off any rust that is present on the skillet. Rust can hide damage or past repairs to the pan, handle and lid.
Examine the cast iron skillet to determine its condition. Look for evidence of repairs, such as welds on the back of the skillet or paint on the inside surface. Look also for replacement parts, dents, holes, damage to the hinge in skillets with hinged lids, pinholes and bubbling in porcelain and enamel-coated skillets, or warping and cracking. Damage and repairs will lessen the value of the skillet.
Identify the brand and style of the skillet by looking on the bottom of the pan. Early cast iron skillets did not always have the brand imprinted, however. Some companies placed the city of manufacture on their early cast iron skillets instead. Griswold skillets, for example, are marked "Erie." Other companies used logos or other symbols.
Look on the back of the pan to see if it has size and pattern numbers. Pans manufactured with the number 1 are in great demand and have the most value. Collectors also look for pan size numbers 12, 13 and 14. Skillet lids also have value and you can sell them separately if a pan is missing or damaged.
Check with an antique collector to determine the rarity of your cast iron pan. A model that introduced a new feature, such as a shaped handle or a hinged lid, is much more valuable than second-generation pans with the same feature.
Determine the average recent selling price of your cast iron skillet by checking with major auction houses and Internet auction websites. When comparing your skillet to recent sales, make sure the description and condition of the auction skillet is the same as yours. If prices were similar across five or six auctions, you can compute the average value of your cast iron skillet.