The value of an antique stoneware pickle crock can be estimated by checking through completed online auction listings or by asking an antiques dealer that sells similar crocks. The value of any single crock depends upon the crock's condition and rarity; some types of pickle crocks are quite common since many exist, so they may not be worth much even though they are old. Even a small crack can detract from the crock's value.
Check the crock to locate any identifying marks, such as artwork or lettering. Inspect the crock closely to find a small stamp or embossed area indicating the maker of the crock. Sometimes this mark is on the bottom. Also check for tiny cracks or chips that detract from the value. Look for identical or similar crocks on auction sites, seeking out auctions that have already ended to get an estimate of how much your crock may be worth. If you feel your crock is rare or unique in some way, ask an antique dealer to estimate your crock's value at current market prices. Seek out online forums run by collectors or dealers of stoneware crocks. In some cases, you can ask questions or email pictures of your crock to get additional opinions about its value.