Why is the Gankun circle not good after it is left at home?

This is not good. 1. Gankun Circle is an outdoor object with dust and bacteria on it. Don't bring it into the house until it is cleaned. Second, the circle weighs 2-3 Jin, and the excircle has an acute angle. If the children at home are curious to play, it is unsafe. Third, the true nature of the circle is a self-defense weapon of Taoism, which is not suitable for entering the homes of ordinary people.