Yes, Muyu stone is a natural ore that used to be a combination of wood, ore and soil, but its heat resistance is not good, especially in winter, when boiling water is poured directly, 99% of it will be fried, so it is most convenient to preheat Muyu stone with warm water before each use. The whole barrel can be boiled in any cup, or it is now quenched and fired at high temperature to prevent cracking.