your stamps by keeping them in dark folders, plastic boxes, or drawers (locations with higher humidity can leave mounted stamps on shelves as long as no direct sun can get to them).
your stamps with plain glycerin to rehydrate and protect. Glycerin keeps the rubber moist and preserves its life, especially in dry climates. Rub a little on with your finger or a soft brush, and wipe the excess off with a soft cloth. Glycerin comes off with water.
Glycerin can also be used as a release agent when stamping into polymer clay, although embossing ink is great for that use, too. I’ve seen glycerin bring 70-year-old stamps back to life.
Glycerin is available at drug stores or pharmacies.
Instead of glycerin you can use clear embossing or watermark ink as a protective coating. That, too, will wash off with a little water on a cloth or stamp scrubber.
Never put oils, vegetable, butter, or mineral, on rubber or polymer stamps, as that would ruin stamps from ever holding ink again. Over time oils will turn rubber to mush. Use oils ONLY if you are using a stamp exclusively for cookie making or other culinary application.
Alcohol and other solvents should be avoided when cleaning rubber, as they will cause the rubber to dry out and crack, and that’s what we are trying to avoid.