The first obstacle many stamp collectors encounter is removing stamps from envelopes so they can be displayed in an album, stock book or other means. Traditionally, stamps were affixed to envelopes with water- (or saliva) activated glue. Since the 1990s, stamps have become increasingly self-adhesive. The U.S. Postal Service developed self-adhesive stamps to keep them from being soaked off and attempted to be reused. This makes it more challenging for collectors to remove them from backing paper. The best way is still the age-old soaking method, with a few modifications.
Separate stamps on colored paper from those on white paper. The colors in the backing paper (envelope) may bleed, and to be safe colored paper should be soaked separately.
Use room temperature to warm water. While water-activated stamps soak off in cold water, self-adhesive stamps need warmer water. Do not use hot water.
Place stamps face down in about 3 to 4 inches of water in a clean sink or plastic tub. Gently press the stamps and paper into the water to make sure they are submerged. Mystic Stamp Company recommends not soaking more than 50 stamps at one time.
Soak self-adhesive stamps for 15 to 25 minutes or up to an hour. Self-adhesive stamps require more soaking time than other stamps, and a few might not soak off at all. Check stamps after 15 minutes to see if they are starting to loosen from their backing paper.
Remove promptly stamps that have loosened from their backing paper. Self-adhesive stamps may not float freely and might need to be gently peeled off. Do not force stamps from backing paper and stop if they do not peel off easily. Be patient. If they do not peel off after an hour of soaking, it is best to abandon soaking. Dry the problem stamps and very carefully trim the backing paper close to the stamp edges.
Use tongs to carefully remove stamps from water and place them face down on blotting paper. Plain white, not printed, paper towels will work fine.
Add more blotting paper on top of the stamps and allow them to partially dry for 15 minutes.
Add a sheet of wax paper on top of the blotting paper and place a large, heavy book on top of the stack to keep the stamps from curling. Allow them to dry overnight or until completely dry.