To modern readers, this might sound bizarre.
But in ancient Rome, urine was a valuable cleaning product.
The reason lies in chemistry.
Human urine contains ammonia, which acts as a natural cleaning agent. Ammonia helps break down grease and stains, making it effective for washing fabrics.
In Roman cities, large public containers were placed on street corners for people to urinate in.
The collected liquid was then taken to laundries called fullonicae.
Workers known as “fullers” used the urine to clean clothing, especially wool garments.
The cleaning process often involved workers standing in large tubs and stomping on fabrics soaked in the ammonia mixture to remove dirt and oils.
This method worked surprisingly well.
The practice became so widespread that Emperor Vespasian even introduced a tax on urine collection.
When his son criticized the tax as unpleasant, Vespasian reportedly held a coin up to his nose and asked if it smelled. When his son said no, the emperor replied with the famous phrase:
“Money does not stink.”
Despite the unusual method, Roman laundry services were highly organized and effective.
The practice demonstrates how ancient societies used practical chemistry long before modern science explained it.
What seems strange today was simply resourcefulness in the ancient world.