Soap nuts are found in both the eastern and western hemispheres, but are native to India and Nepal. They have recently become a popular environmentally friendly alternative to chemical detergent, and are a gentle option for those with allergies to chemicals in regular detergents. Soap nuts contain saponin, a natural detergent. The soap nut shell absorbs water and releases the saponins which circulate as a natural surfactant in the wash water, freeing dirt, grime, and oils from clothing. There is considerable discussion as to what variety of Soap Nuts is preferable for use as a laundry soap alternative. Any Soap Nut from the genus Sapindus will work just fine as they all have Saponin producing properties, hence the genus name Sapindus.
The husk or de-seeded nut.
Just a few nuts (4-6) in a cotton muslin bag should work for an entire load. There will be little or no bubbles during the wash cycle, and it will smell lightly similar to apple cider. They can be used several times and then composted afterwards. They will look mushy and grey when they need to be changed. They can also be used in a powder form as a cleansing cream by adding a small amount of water.
Soap nuts can be used for anything that you would normally use detergent for; washing the car, windows, etc. Some people have used them as a base for shampoos and hand lotions, and as an all purpose cleaner for around the home. They can be used as an anti-microbial for septic systems. Jewelers in India and Indonesia have used them to remove tarnish from jewelry and other precious metals for many centuries.