[eichin]

I remember a scratch-and-sniff version, rather than just scented (in western CT, in the 1970s - they must have bulk sent them, noone in the neighborhood actually had gas service so it wasn't in with gas bills.) That's enough to find https://hackaday.com/2024/12/03/scratch-and-sniff-stickers-a... and the search https://www.google.com/search?q=scratch-and-sniff+mercaptan&... actually turns up a bunch of present-day gas vendors that will send them to you on request!