If you are just starting your collection, or are specializing in modern definitives, and are collecting used stamps, one of the most economical sources of stamps for your collection is killoware. Killoware refers to stamps that have been clipped from envelopes and are still on the original envelope clipping. If the clipping includes both the front and back side of the envelope from which the stamp came, then the stamps are said to be on double paper. Otherwise they are on single paper.
The question quickly arises as to what to do with the stamps on paper? The conventional wisdom 30 years ago was to soak all of them in water to get the paper off and then dry and press them. If you are not interested in collecting cancellations (postmarks), then that still applies today. However, if you are interested in collecting cancellations, then it is probably best to leave them on piece, provided that the piece contains the entire cancellation, with a reasonable border around. These can then be displayed in your album. If the stamps are self-adhesives, it is also probably better to leave them on piece, as these can be next to impossible to soak off, as the gum is often not water soluble.
Once you have decided which stamps you wish to soak, there are a few important points to note, so as not to damage your stamps:
- For most stamps, it is generally best to soak them in cold water or lukewarm water. You should never use hot water, as this tends to soften the inks used to print photogravure stamps and can cause surface wrinkling, or loss of colour from the stamps on the drying cloths.
- Separate stamps on coloured envelope papers, such as yellow, green or red from those on white paper and soak them separately. These envelopes often contain water soluble dyes that will run in water and can stain the stamps that are on them. One trick that I learned for dealing with this when I was younger, is to add a bit of salt to the bath water beforehand. This can help prevent the colour from soaking into and staining the stamps. In any event, the coloured papers should be further sorted and soaked separately: red with red, yellow with yellow, etc.
- Add the stamps to the bath water and when finished gently immerse them by pressing down. It will take a good 30-40 minutes for the water to penetrate the paper completely and loosen the gum enough to be able to get the stamps off the paper. Generally the stamps are very fragile when damp, so my preference is not to try and peel them from the envelope paper at all. Rather, I prefer to go through the water and pull out any pieces of envelope paper that have no stamps, remove the stamps that have floated off and place these in a separate bath. This separate bath helps remove any residual gum, which will prevent them from sticking to the paper towels that you will be drying them on later. Then, I will usually dump out the main bath water and re-fill it, repeating the process. Eventually 90-95% of the stamps will have floated off the envelope paper, leaving a small amount that you will have to manually peel off.
- In peeling the stamps off the envelope paper, the safest way to do this is to hold the stamp firmly and starting from one corner, peel the paper away from the stamp, and not the other way around. The difference is a subtle one, but if you peel the paper away from the stamp, you have a much lower chance of damaging the stamp. DO NOT force it. If you encounter any resistance, stop and either place the piece back in a new bath, or consider drying it out on piece and leaving it the way it was.
- When you have all the stamps in the second bath, and you have changed the bath water to the point that it is no longer murky, then you will know that you have washed away all the gum and are now ready to dry the stamps and press them.
- There are two ways that you can dry and press your stamps. One way is to get several layers of paper towel and a large heavy book, like a dictionary or other heavy book, and make a drying area from paper towel in the approximate shape of the book. Then place the stamps face down on the paper towel, cover with 1-2 layers of paper towel and repeat, until all your stamps have been placed on the paper towel. Then place the book, on top of the paper towel, add some other books for weight, and wait 1-2 days. Then remove the book and the top layer of paper towel. Depending on how wet the stamps were and how much paper towel you used, you will either have flat, but very damp stamps, or relatively dry, flat, but somewhat damp stamps. Depending on how damp the stamps are, you will probably need to air-dry them before you can put them away. Air drying them will be no problem if you have removed all the gum, as they should dry flat, even after you remove the book. After they have air-dried, you should be able to mount them or put them away.
- A second way to dry and press your stamps is to place them face down on paper towels in a single layer, and air dry them. Once they are almost dry, being slightly damp, you can then place them on paper towels with the book on top to press them completely dry. The only drawback to this is that if the stamps curl or shift when you are placing the book on top of the paper towels, you can wind up creasing some of your stamps. You have to be very careful when doing it this way. One advantage to laying them wet on the paper towels is that they tend to lie flat, so there is very little chance of creasing them when you place the book on top of the paper towel. But if they are already mostly dry when you do this, then they can curl unexpectedly.
There are liquid "stamp lift" solutions on the market that will work on self-adhesive stamps and some of the more stubborn gums. They are not cheap and come in fairly small bottles. So, for general stamps that you are not planning on mounting, I would be tempted to simply leave those on piece if they won't soak easily. Some people have had success with organic solvents like lighter fluid, or acetone (the active ingredient in nail polish remover). However, I do not advise this generally, as it may also loosen the design. Whether it will or not depends completely on the chemical makeup of the printing ink, and this will be different for each stamp issue. So, unless you know for sure that an organic solvent will not affect the ink, it is probably best to just leave those stamps on piece.