1. When the walnut peeling hand is black, you can use salt to smear it on the stain, then dip it in water to moisten it, and finally wash it with soap.

2. When the black on your hands is dry, you can also rub it with vinegar and then wash it with water, and then you can clean it.

3. You can also peel a few grapes to eat, so that the black walnut on your hand will be cleaned by the fruit acid in the grape juice.