Preparation: Sort the darkened beans.
Wash beens 3-4 times. Put the beans in a pot and sink for 3-4 hours.
Pour out the sink water and cover the beans with clean water. Boil the beans for 15 minutes and then grab it. 1½ hours until the beans are soft.
Make sure there is enough water in the pot.
Beans are ready for eating or other dishes.