You’ve found a stamp that fits perfectly into your stamp collection. The face of the stamp is unblemished. The edges have no tears, and the stamp looks to be in near mint condition. Unfortunately, the stamp is either stuck to an envelope or has unsightly glue on the back. Due to the age of the stamp, using the floating technique -- immersing the stamp in a bowl of cool water -- is out of the question. The floating technique can damage a stamp if the cancellation ink bleeds into the water and stains the stamp. Instead, use a sweat box to remove glue or separate the stamp from its envelope.
Activate the sweat box. Remove the spacer. Pour warm water over the bottom sponge. Use enough water to thoroughly saturate the sponge.
Place the spacer back on the top of the sponge.
Place the stamp face up on the spacer.
Replace the lid on the sweat box.
Remove the lid after 30 minutes. Gently remove the stamp from the sweat box with stamp tweezers. Check the progress of the stamp. Peel paper away from the stamp or touch the glue on the back of the stamp with your finger. The glue becomes soft and gummy as it wears down.
Return the stamp to the sweat box for another 30 minutes. Check the progress. Continue this process until the glue is gummy and loose on the back of the stamp.
Remove the stamp once the glue is very loose or almost gone.
You can make your own sweat box with an airtight plastic container, a kitchen sponge, two bottle caps and a sheet of plastic. Place the sponge at the bottom of the container. Place the bottle caps on either side of the sponge. Poke holes in the sheet of plastic. Place the plastic on top of the bottle caps. Pull excess glue off the back of stamps with a pair of stamp tweezers. Gently pull the glue off to avoid ripping the stamp. Place damp stamps on a paper towel face down. Allow the stamps to thoroughly dry. Flatten curled stamps by pressing between two heavy books for a week.
Do not move the sweat box while it is in use. Do not attempt to remove glue with tweezers if the glue is stubborn.