I think if I were in the south, I wouldn't have to tear it ~ for one thing, they have many hats, and for another, their air environment is good. If I am in China, as I am in Beijing, my hat will be dirty and difficult to wash after going out for a day. After being dirty, the standard is aging. If I have to tear it off again, there is a particularly obvious small circle on the hat ~ this is the original target position, and everything around it is dirty ~