“Lōtium” is the basic Latin noun for Urine, relating to “lavāre,”: To Wash.
In the pre-Soap Roman era, people preserved urine in cisterns, using the ammonia to wash their clothes. Some even washed their teeth with Urine, which resulted in very white teeth and even a poem by Catullus (Verona, 82BC-54BC) about a man
called Egnatius, who was prone to do just that:
Egnativs, because he has white teeth,
is everlastingly smiling.
If people come to the prisoner's bench,
the counsel for the defence
is making every one cry,
if they are mourning
at the funeral of a dear son,
when the bereaved mother
is weeping for her only boy,
whatever it is, wherever he is,
whatever he is doing,
it is a malady he has,
neither an elegant one as I think,
nor in good taste.….
there is nothing more silly
than a silly laugh.
As it is, you are a Celtiberian;
now in the Celtiberian country
the natives rub their teeth and red gums,
every morning with what they have urinated,
so that the cleaner your teeth are,
the more urine you are shown to have drunk.
This of course is an allegory, and nowadays we wouldn’t say that Egnatius was drinking urine and therefore smiling, but that he’s been ‘licking asses’ and therefore successful.