How to Identify Valuable Stamps

Identify the denomination (amount the stamp originally cost) and color, and check it against the stamp identification section in the Scott Postage Stamp Catalog. The Catalog has basics of what stamps are now worth.

Measure the edge of the perforation (the white torn edge around the stamp) and make sure it's in good condition. If there are rips or tears in the stamp, or if one edge of the perforation is gone, the stamp will most likely not be worth much. Also, unused (known as "mint condition") stamps make up the bulk of collected stamps, and almost all of the valuable ones. Some people collect used stamps as well and keep them as a second collection, but usually as novelty items, as they are rarely worth much.

Look at the watermark of the stamp in good lighting. The watermark is a pattern on the paper the stamp was printed on, and sometimes identical stamps will have different watermarks (making it a different stamp to a collector). It will usually be a symbol or letter, or a simple pattern. If the stamp was issued after 1917 it probably does not have a watermark. See reference for Linn's Online, which can provide more details about watermarks.

Restore all the stamps between sheets of acid-free paper in sealed plastic bags and keep them away from water and humidity.

Take the stamp to be professionally graded if it's in good condition and has a good listing in the Scott Postage Stamp Catalog. You can take it to a local stamp shop or contact a professional stamp grading service such as Professional Stamp Experts (see Resource).