Soap Nuts come from a soap nut tree and are actually an alternative to soap when washing your clothes. I have not personally tried them, but if you google them, you may want to check them out.
One of our readers, Kim, is trying them out right now and will keep me posted. So far, she says , "The soap nuts work OK, but they are a pain to use. Our water is so hard that I have to boil the berries to get the soap out and add salt to the water. I may try grinding them up and see how that goes."