Rinse with urine for dental health

It wasn’t until 1780 that a man named William Addis invented the first mass-produced toothbrush, and it took a century before the tool really caught on in the United States. 

Before then, toothbrushing practices varied alarmingly: Pierre Fauchaud, known as the father of modern dentistry, was a proponent of the theory that rising with one's own urine can cure a toothache. 

His theories would strongly influence dentistry for the next hundred years. 

He wasn't completely nuts—pee is rich in ammonia, which is a base, and can thus neutralize the acid that tooth-decaying bacteria produce. 

In the 19th century, some working class families unable to afford soap used it to clean dirty clothes.