> Because urea in urine breaks down into ammonia, urine has been used for the cleaning properties of the ammonia therein. In pre-industrial times urine was used

> Because urea in urine breaks down into ammonia, urine has been used for the cleaning properties of the ammonia therein. In pre-industrial times urine was used – in the form of lant or aged urine – as a cleaning fluid.[25] Urine was also used for whitening teeth in Ancient Rome. https://en.wikipedia.org/wiki/Urine#Cleaning https://en.wikipedia.org/wiki/Urine#Cleaning