Maube just some old yellowed wax/polish, try some "00" steel wool & rubbing alcohol, it wont scratch the chome at all, I've also use white wall tire cleaner, its called " blech-white" just spray the steel wool, not the painted surfaces of the machine as it can dull the paint, wipe/rinse after with a water wetted cloth
I concur. Seen this sort of material in the past, and the chrome polishes right up.