Collecting postage stamps, also known as philatelism, is a satisfying and popular hobby. Many stamps people collect are not particularly valuable, but some rare and old postage stamps can be worth a lot of money. Most old stamps are higher in value when unmarked, and misprints may be worth even more. If you've inherited or purchased a stamp collection, selling some or all of the most collectible specimens may be a good idea.
Analyze any gathered collections. Check for themes, such as country of origin or common year. Complete collections of related stamps are usually worth more than collections or books containing mismatched or random stamps, no matter their age.
Preserve other materials that may be worth as much or more than the stamps themselves. According to the experts at the Stamp Domain website, sent envelopes can have rare stamps attached. When intact and in good condition, they can be worth more than the stamp alone. Aged philatelic literature, such as pamphlets or books, can also be very valuable.
Appraise the stamps yourself using a copy of the "Scott Postage Stamp Catalog." The American Philatelic Society recommends this six-volume set as the best method for appraising the worth of postage stamps without the help of a professional.
Bring the collection or particularly interesting postage stamps to a stamp dealer or professional appraiser. Peter Aitken explains on his stamp collecting website that an appraiser may give you a more fair estimate because they are not interested in purchasing the collection. A dealer may offer you an amount immediately to purchase the collection, but it can be hard to know if they are making a fair offer.
List the most valuable stamps, or the whole collection, for sale on a stamp auction website. There are also a wide variety of stamp selling periodicals published around the country which will publish your offers for a small fee. Contacting a stamp club, especially for specialty stamps, is another good way to generate sales and interest.
Randomly gathered, damaged, and recently issued stamps are rarely worth a high price. Look for organized, themed collections or stamped and used envelopes. Visit a local stamp club for help finding a reputable local dealer. They will have more information on local stamp enthusiasts than other sources. Be sure to do some basic research on the value of your stamps before contacting a professional appraiser. The fee for appraising can be high, and may not be worth it if all of the stamps have an obviously low value.
Do not attempt to remove old postage stamps from envelopes, no matter how damaged the envelope. These stamps can be damaged in the process, and are usually worth more on an envelope. Do not sell a collection for the first offer you receive. Many dealers and collectors will offer you far less than it is worth if they know you are unsure of a collection's value. If you receive higher offers than you expected, contact an appraiser.