The pressure cooker has been used for a long time, and there is a layer of gray in it, which can be used continuously. As of January 2, 223, according to the relevant public information, the bottom ash of the pot was caused by the fact that the returning soup was not cleaned in time when the vegetable juice overflowed or poured. When washing the pot, the cleaning outside the pot was often neglected, so that a thick bottom ash was formed on the bottom of the pot over time. Usually, when washing the pot, both the inside and outside of the pot should be cleaned, so that it would not be formed.