Some of the greatest stamp collections in the world include postally used stamps that have been removed from envelopes.
To separate stamps from envelope paper, collectors soak them in water, which weakens the stamp glue and allows the stamp and paper to drift apart.
Although this method is used by thousands of collectors around the world, it is important to inspect any cover (which is a mailed envelope or postcard) before deciding to soak off the stamp.
It's fine to soak common stamps that are used in an ordinary manner, but covers that show special rates, unusual usages or hard-to-find stamps are best saved intact.
For common used stamps, the safe way to remove them from the envelope paper is by soaking in water.
Even if a stamp appears to be barely attached to the envelope, giving it a tug to remove it from the paper will probably damage it, either by creasing, or by creating a "thin" in the paper. A "thin" is a section on the back of the stamp where the paper has been partially peeled away.
To prepare a stamp for soaking, the stamp should be carefully clipped from the envelope (Figure 1), leaving enough paper around all of the stamp edges so the scissors do not clip any part of the stamp.
A collector can soak numerous stamps at the same time. A beginner can start with 20-30 stamps, or even fewer, to get used to the various soaking procedures.
Two pans or bowls are needed to soak the stamps. Both pans need to contain clean, room-temperature water, about one-half inch in depth. If large quantities of stamps are being soaked (say, from a big stamp mixture purchased from a dealer), then a little more water may be needed.
The clipped envelope corners bearing the used stamps should be added to the water a few at a time.
Some collectors prefer to place the stamps in the water face up, as shown in Figure 2, because it is easy to see when the stamps have floated free of the paper.
Because the stamp paper tends to float near the surface of the water, other collectors prefer to place the stamps in face down, so that the stamp remains in the water, and only the back of the paper is exposed to the air.
Either method should work fine. Stamps that are soaked using the "face-up" method may need to be gently pushed below the water's surface now and then to keep them well-soaked.
Some stamps will float away from the envelope paper in just moments. The loose paper can be discarded, and the stamp can be transferred to the second pan of clean water. This second bath will serve as a rinse to help soak off any stamp adhesive residue or envelope dye that may be in the first bath.
The rinse can last from just a few minutes to a half-hour or so. Longer soaking may cause the stiff stamp-paper fibers to weaken.
A good stamp-soaking tool is a pair of spade-tip stamp tongs. Tongs can be used to gently dunk the floating stamps in the first bath, and (as shown in Figure 3), can be used to easily remove the stamp from the soaking water.
The flat spade tip holds the stamp securely, but shouldn't tear through the wet stamp paper, as pointed-tip tongs might.
Because of differences in stamp adhesive, some stamps may require a longer stay in the first bath. British stamps often hang tough onto envelope paper, but will release in time.
A big mistake is trying to peel a wet stamp off the paper before it is ready. If the glue doesn't want to let go yet, it's more likely that the fragile wet stamp paper will tear or thin.
Stamp soaking often requires patience.
Some self-adhesive stamps, including U.S. self-adhesives issued during the early 1990s, can be very difficult to separate from stamp paper. The collector has two options.
Soaking self-adhesives in water up to 30 minutes will usually loosen tenacious stamp gum. The stamp will either float free, or the collector can slowly separate the stamp and the paper by carefully sliding the spade-tip stamp tongs between them.
It may be necessary for the collector to manually remove adhesive residue from the back of the wet self-adhesive stamp. To do this, the damp stamp should be placed face down on a flat surface. As the collector gently rubs the back of the stamp with a finger, the adhesive should ball up and come off the stamp.
This method may damage the stamp, and should first be practiced on a common stamp that is easily replaced.
The second option is to save the stamp on-paper without soaking it, either by trimming the envelope paper around the stamp, leaving an even margin of paper, or by keeping the cover intact.
After the rinse bath is complete, the stamps can be removed one by one, and placed face down on a towel, blotting paper, or firm absorbent paper.
Figure 4 shows wet stamps that are air drying on a black towel.
After 10-15 minutes, much of the excess moisture will be gone, but the stamps will still be damp. The next step is to complete the drying process and flatten the stamps.
The stamps can be placed face down on a clean piece of unprinted cardboard like the type used to make cereal boxes. The stamps should not touch one another. When the cardboard is full of stamps, a sheet of wax paper covers them, and a second piece of cardboard covers the wax paper.
If there are more stamps to flatten, the second piece of cardboard should be placed with the unprinted side up, so a second layer of damp stamps can be arranged on it.
More wax paper and cardboard are added until all the stamps are ready for pressing.
As shown in Figure 5, a heavy book or two placed on top of the layers will add enough pressure to ensure that the stamps will be flat and dry in about 12-18 hours. A little extra time under pressure helps to prevent the stamps from curling after they are exposed to air.
Collectors can buy specially designed stamp drying books to make this part of the experience a little simpler. The book contains several absorbent pages interleaved with several sturdy glossy pages. The adhesive side of the damp stamp is placed on the glossy page, and it is covered with the absorbent page.
The stamp-drying book produces flat, dry stamps and can be used repeatedly.
After drying, the stamps can be added to the collector's stock book or stamp album, or stored in glassine envelopes.
Here are a few hazards to watch out for.
Don't use water that is too hot, as it may fade the colors of some stamps, or scald the collector.
Stamps that are affixed to colored paper should be soaked separately. The dyes used to create colored envelopes often run in water, and stain all of the stamps in the bath.
The color of manila envelopes may run in water, but the worst offenders are dark green or red holiday envelopes (Figure 6).
Separate stamps on these papers, and soak them one at a time in cold water. Remove the stamps immediately when they are free of the paper, and rinse in clean, warm water.
Change the water in both baths for every stamp on colored paper that you soak.
Even with special care, the envelope paper may stain the stamp.
Every collector who soaks stamps develops individual habits and methods. Additives to soaking water are not recommended, as the effects of chemical residue could harm stamps over the long term.
Stamp soaking is a relaxing way to prepare postally used stamps for placing them in your collection.