How did the ancients get their hair cut?

"The Book of Filial Piety" said: "Parents who suffer from skin damage dare not." So the ancients didn't cut their hair or nails? It is basically reasonable. For too long, it was just an ancient feudal thought. There is a superstition about cutting hair. When the hair is over the waist, you should turn over the yellow calendar and choose an auspicious day. In addition, the ancients washed their hair with so-called "tea oil soap". Earlier, they used clean water. Some people soak sawdust in water to reduce the greasy smell of hair by the smell of sawdust. As for the rich, there are many tricks. As for nails, the ancients thought that nails were stagnant gas, and not cutting them would inhibit the outflow of turbid gas. Nails did not belong to the category of body hair and skin.