Most often when I tell people I do my laundry with soap nuts they ask “What are soap nuts?” And that’s an excellent question, because they aren’t very well known yet, even though they are amazing. Soap nuts are not actually nuts, but they are a berry that grows on a tree from the Sapindus trees. These trees grow in warm locations, and all the ones I have seen for sale have come from India. I believe they are called nuts because they look a lot more like nuts than berries. But the really cool thing about them is that when the husk of the dried berry gets wet it releases saponin, which is a surfactant, which is what makes soap useful to clean with. So essentially, soap nuts a like soap from a tree. Awesome! The really awesome thing about soap nuts is they are hypoallergenic, grey water safe, and environment friendly. Even the most mild homemade laundry detergents usually contain borax and washing soda, which is none of the above. The only down side to soap nuts is that they are imported, but for me the benefits outweigh their long distance travel so I use soap nuts almost exclusively.