Generally, most of them are animal blood residues, which are formed after high temperature cooking. I don't know if you have noticed that you usually boil meat dishes in a boiling water pot before cooking them. That's why. Also, in our hometown and countryside, when we were young, we pickled bacon at home, and every once in a while, we would beat out the salted salt water and burn it, and there would be a lot of white foam on it, which would also be removed, and then the salt water would turn from red to white. . I suggest that you get rid of the foam in the hot pot. In general hot pot restaurants, you do it yourself. If it is a high-end hot pot restaurant, you can ask someone to help you.