How To Save Self-Adhesive Stamps
Self-stick, "no-lick" stamps are a special problem for stamp collectors, although no one denies that they're great for using on mail! That's why you are seeing more and more of them issued--the U.S. Postal Service says the public wants them, and estimates that the great majority of new U.S. stamps will be self-sticks within the next few years.
One problem for collectors is that all self-sticks are not created equal, so there are no general rules about saving them. At least in this country, self-adhesive stamps have been a learning process for the manufacturers, and have changed over time. The first U.S. self-adhesive stamp, a precanceled stamp showing a dove weathervane and issued for Christmas in 1974, had the adhesive applied directly to the back of the stamp paper. Many of these stamps are now discolored by the adhesive migrating through the paper and around the edges. The early self-sticks also could not be soaked off paper in water.
More recent self-stick U.S. stamps seem to be much improved. Current U.S. self-sticks have an extra layer of paper between the adhesive and the paper the stamp is printed on, so a collector can soak the stamp off paper in the same way that a gummed stamp can be soaked. And, some people believe that a self-stick should be soaked, because the adhesive can still migrate around the stamp's edges and be destructive over time.
These collectors do not think that it is a good idea to save "mint" self-sticks - for example, cutting one stamp off a sheetlet but leaving it attached to its backing paper, or cutting it off an envelope and leaving it attached to the paper. Only time will tell who is right about this, when it is possible to see the results of the various methods of storage.
But, self-sticks do take longer to soak, and some collectors report self-sticks disintegrating in the soaking bowl, or not flattening out as nicely as gummed stamps do after soaking.
One way to deal with self-sticks is to hedge your bets and save duplicate examples: one on its original paper, one on cover (or on a trimmed piece of cover), and one soaked. That way, depending on what might happen as the adhesive changes chemically over time, you may end up with three examples for your collection, but you should certainly have at least one good one!