The traditional biscuit snack "tui" is made of milk residue and ghee. Milk residue with ghee is extracted from grandma Niu. After the milk is broken into ghee, the remaining milk is boiled with fire and cooled to form yogurt water. Milk residue is poured into the bamboo bucket filter and left in the bamboo bucket filter. Milk residue is white and sour, which is very helpful. Tibetans who go out often bring milk residue to prevent water and soil discomfort. At present, all kinds of food stores and restaurants in Diqing Tibetan area have recipes for frying milk residue, and the production process is very fine.