I did some searching up on this "infamous Vespasian urine tax" because uh what 😂. Nero apparently started it, then it was stopped, and Vespasian re-enacted it. Urine collected from public urinals was sold for chemical processes (like they mention, tanning, laundry 🤢, etc) and the businesses buying the urine now had to pay a tax. Pecunia non olet, money does not stink. Those who speak Italian and French already know all this because vespasiano/vespasienne still refers to public urinals, in honor of this tax 😂 All from this Wikipedia article: https://en.wikipedia.org/wiki/Pecunia_non_olet