2, microwave ovens should use less brightly colored containers. It is best not to use patterned mugs. Unless the underglaze process is adopted, heavy metals such as lead and mercury in these pigments will precipitate at high temperature, which will cause damage to the liver and kidney of human body. So if you use plain ceramic cups, you can put them in the microwave oven. If there is a pattern on your mug or there is no indication that the microwave oven is available, it is best not to put it in the microwave oven for the sake of health.