For you kids, a “pay phone” is something old people used to use to call other old people.
Heather @ NewYorkShitty hazards a guess that that substance is cheese. She doesn't say if she smelled it or not. A commenter says it's mortadella. Snapped in Brooklyn.
For a steady diet of photos of seriously fucked-up NYC pay phones, bookmark New York Shitty. It is a must daily visit if you want to keep up with NYC street art/animals/weird things.
Via: newyorkshitty.com