I have only seen Cattulus mentioned as a source for the teeth cleaning part, but generally, is there enough in the sources to establish a picture of what Romans' relationship with their bodily waste was when it came to practical usage? Was urine the best way to get ammonia?
I can’t speak for using urine for cleaning teeth, but I can speak for its use in producing textiles. Most of my understanding of these processes come from archaeological findings at Pompeii.
Urine was incredibly useful for treating wool, dyeing fibers, and cleaning clothes at establishments called officinae lanifricariae, officinae tinctoriae, and fullonicae respectively.
Officinae lanifricariae were the workshops where wool was cleaned and prepared for textile production. Here untreated wool was soaked in stale urine in large vats because urine could dissolve the lanolin (a wax/grease that is secreted by the sheep/wool-bearing animals).
When dyeing clothes in officinae tinctoriae, romans would treat their wool with urine again because it was a mordant agent. Mordant agents ensured the dye would stick.
At fullonicae, urine and sulphur were used to clean and bleach fabric. The effects of using urine indoors can be seen at one fullonica in Pompeii (VI.14,21-22). This workshop had its cleaning vats and rinsing basins in a very secluded part of the building most likely to isolate the smelly practice from the patrons who came to pick up their clothes in the front. It is suggested that these buildings also had a channel leading from the street to the inside where they could collect urine.
In these industries urine wasn’t just used in cleaning clothing—it served many functions.
It is important to stress that the guild of fullers (those who worked in textile industries) held a bit of power in Pompeii. One of the main buildings situated on the forum, the Eumachia building, was dedicated to a local priestess. She was a bit of a political celebrity and was recognized as the mother of the fullers. Her statue in the Eumachia building was dedicated by that guild. It has been debated whether the thriving textile industry at Pompeii was simply the product of local demand or was for export elsewhere in the empire. Regardless, because of its prominent textile industry and the use of urine in all three processes, Pompeii had a strong demand for urine.
And was urine the best way to get ammonia? Moeller, one of the experts on the textile industry in Pompeii, briefly mentions other alkaline agents that may have been used to remove lanolin from wool—soda (nitrum) and potash (a vegetable fiber ash). But he stresses that because the ammonia from stale urine is the mildest and most abundant source, it was the most important agent in textile production in Pompeii (and probably in the rest of the empire as well). And this honestly makes a lot of sense to me. Urine is very easy to obtain—anyone can make it.
I hope this helps a bit!
Sources:
Flohr, Miko. 2011. “Reconsidering the atrium house: domestic fullonicae at Pompeii.” In Pompeii: Art, Industry and Infrastructure, edited by Kevin Cole, Miko Flohr, and Eric Poehler. Oxford ; Oakville, CT: Oxbow Books.
Laurence, Ray. 2007. Roman Pompeii : Space and Society. 2nd ed. London: Routledge.
Macmahon, Ardle, and J. Price, eds. 2005. Roman Working Lives and Urban Living. Oxford : Oakville, CT: Oxbow Books.
Moeller, Walter. 1962. “The Woolen Industry at Pompeii.” Dissertation, University of Maryland.
Pirson, Felix. 2008. “Shops and Industries.” In The World of Pompeii, edited by John Joseph Dobbins and Pedar William Foss. New York: Routledge.
If anyone is going to tackle this, can I follow up ask if the urine used by a person was always their own? And if it wasn't, I am interested (and slightly disgusted) to learn the procurement process.