The name Soap Nut is misleading for it is the shell that actually works. The soap nut SHELL contains and releases the saponins (soap) when it comes in contact with warm or hot water. Agitation or rubbing further releases these saponins. The saponins then circulate as a natural surfactant (surface active ingredient). They break down the surface tension between water and oil in the wash water reducing the surface tension of the water aiding it in freeing dirt, grime and oils not only from clothes but also every surface. Essentially this is the exact same fundamental principle that applies to how most detergents and soaps work. It's simply not achieved via the use of synthetic chemicals.
The name saponin is derived from the Latin word 'sapo', which means soap. There are many plants around the world that are saponaceous (meaning that they contain saponins) but only a few, are known to produce appreciable amounts. Hence, this is why soap nuts are so very special in their ability to be an effective cleanser - directly from the tree. Our Thailand grown Sapindus Rarak trees have been found to produce the highest and most consistent quality soap nuts.
Ready for use by the end user directly from harvest, extraction of the saponin from the soap nuts requires nothing more than putting them directly in the washing machine in warm water. Drawstring bags are perfect to contain the soap nut shells, and the shells can be reused until their saponin content has been depleted. Given that the saponins are naturally a low sudsing detergent, they are ideal for high efficiency (HE) washers and even carpet cleaners.