I don't exactly know what a "Zyn" is myself, but from reading the tweet and being a filthy Scandi, I know that must be a snus. It's a small pouch of tobacco which people pack under their upper lip for the nicotine high with less smoke. But it's fooken filthy in itself, and people often leave them everywhere, as annoying as cigarette butts imo. Very popular in Scandinavia, invented by the Swedes and banned in the EU (except Sweden of course.)