Scratch and sniff
The first generation of Scratch and Sniff was basically an aromatic scent of "perfume" with a coat of varnish over the substrate to dry. Scratching the printed piece released the fragrance and only last a few hours or days at most. One of the first books about Apple computers VANLOVES Apple Software Guide (R.Love & J.Vandiver Vital Information INC-1981) had the scent of an eating apple inside the cover. The scents did not last very long. New scent technology will last for years.