You may have bought a bad purple casserole? Purple sand, which is mainly produced by five-color stone oil, has many pores and textures, and is easy to absorb various food ingredients and produce odor. Therefore, the purple sand mainly produced by five-color stone grease should be "pumped (non-) three times and dried." At present, the porcelain glazes of Zisha Gate, Jiuyang and Yili, which are suspected to be enterprise beauty, all contain a small amount of lead, which is easy to dissolve when cooking acidic food and harmful to health. Therefore, it is best to soak the newly bought purple casserole in 4% vinegar before cooking, which can remove most harmful substances. In addition, purple casserole should not contain acidic food. It was reported in the news that a child's mother often used inferior purple casserole to cook soup, which led to lead poisoning of the child because the manufacturer of inferior purple casserole did not inform the precautions.