Stamps used to have a glue on the back that you had to breathe into life by adding moisture. You then had to stick the stamp to the paper envelope as the backing dried. Definitely before the backing dried, as then the stamp wouldn’t stick.
People who had to stick many stamps used a sponge that was slightly damp. They’d wipe the stamp across the sponge then slap it on the envelope or parcel. Clever behind-the-post-office-counter-people, you!
Then the communication powers-that-be brought in stamps that didn’t have moisture-activated gum. In the UK, these stamps first came into circulation in 2001.
Amazing! Stamps you didn’t have to lick. They were self-adhesive — also known as pressure-sensitive stamps. All you had to do was peel them off the backing paper and you were good to go straight to the envelope. Much more hygienic. You didn’t have to lick something (LICK SOMETHING) that someone else had touched.
Great for people who like putting stamps on envelopes. Huge problem for people who like getting stamps off envelopes: stamp collectors.
If there’s no water-based gum involved, you can’t soak your stamps in little saucers to remove them from the envelope then paste them into special albums. You might have to leave your stamps “on piece“, as they say. The world of philately has not — still not yet — recovered from the shock.
Before we had entirely transitioned from lickable to non-lickable, though, I can’t have been the only person who accidentally licked a self-adhesive stamp? This would sometimes wipe off the self-adhesive glue and make it hard to get the stamps to stick to the envelope at all. Yuck.
Sometimes you’d have to lick your envelope closed, too. Actually, sometimes you still have to do that… Only a matter of time, surely?