Certain types of cast iron cookery is worth quite a bit on the secondary and collector’s markets, Wagner being one of them. Wagner Ware, which has a similar name, isn’t connected to this company in any way and still manufacturers cast iron pots and pans today. Pieces from this company are worth less, but still work well for everyday cooking. When you spot a piece of cast iron cookery and you want quality, check the bottom for any signs that Wagner Ware manufactured the piece.
Turn the pan over and look at the bottom. Look for writing on the bottom of the piece, indicating that it was made in Sidney, Ohio. It may have "Sidney, Ohio" on the bottom or just "Sidney O." This indicates that the piece was made by Wagner Ware before 1922.
Look for any sign of the Wagner name, typically labeled as “Wagner" with the name in quotation marks. The company used this early marking prior to 1922, sometimes in combination with the Sidney name. This indicates that the piece is an authentic Wagner.
Check for a Wagner Ware name, along with a Griswold name or a cross inside a circle. The Griswold company sold to Wagner in the 1950s and all the production of those pieces moved to the Sidney location. Pieces from the Griswold molds made after this time period have both names on the bottom.
Compare the type of cast iron piece against known pieces made by the company. Some companies made reproduction pieces, with the Wagner name on the bottom, even though the company never made that particular piece. For example, some companies made a toy size tea pot with the Wagner logo, but the company never made a toy tea pot.
Measure the size of the piece against the dimensions of a real cast iron piece made by Wagner Ware. Often times reproductions are made using the old molds and filling it with foam or another material to create a new one or creating a mold from a specific piece. This causes the reproduction piece to be slightly smaller and thinner than the original.
If you’re really stumped, ask for help from a professional appraiser. The appraiser can look over the piece and tell you who made it and when it was made.