Soap nuts are also called berry shell that naturally contains soap. They grow on the Sapindus mukorossi (Soap Berry) tree in the Himalayas. The natural soap found in these berries is called saponin. Saponin is a natural cleaner that works as a surfactant, breaking the surface tension of the water to penetrate the fibers of your clothing, lifting stains from the fabric, and leaving dirt suspended in the water that is rinsed away.
