Scratch and Sniff Stickers
Scratch and Sniff stickers were first created by a company called Creative Teaching Press in the late 1970's and were marketed as items teachers could give to students as rewards. Some of you may remember getting a scratch and sniff "good job" sticker on your returned assignment (by the way, everyone got the same sticker, so you did not really do as well on that assignment as you thought you did). Generally, the scent of the sticker was related to the image, but this was not always the case. How did they work? The scents were micro-encapsulated onto the sticker. The scent capsules were easily broken when the sticker was scratched, which would release the odor. Eventually, after having scratched the sticker to death, there would be no capsules left to burst and the scent would be faint (or gone). It is worth mentioning that in the 1987, some gas companies began sending post cards out with scratch and sniff gas stickers on them to educate their customers on what a gas leak smelled like. It backfired when they began receiving calls from customers who had not opened their mail yet and thought they had a gas leak in the house.