1. First, crush the main raw materials: soap locust, soapberry, and polygonum multiflorum. If you have a small hammer at home, you can crush them. Then rinse them with clean water and soak them in water for a while. It takes more than half an hour, or longer.

2. Then put the pot on the pot. Do not use an iron pot. Stainless steel or casseroles are all acceptable. Add enough water at one time to be 3 times of the raw materials. Bring to a boil over high heat first, then use low heat to slowly cook. Boil, be careful not to stick to the pot when boiling, otherwise it will burn. It usually takes more than 5 hours to boil. After boiling, filter out the dregs and set it aside to cool down. You can put it aside when the weather is hot. Store in the refrigerator.