Soap nuts are the fruit of various trees that grow throughout India, Nepal and surrounding areas of southern Asia. There are many varieties of 'soap nut tree' including the common Sapindus Mukrossi and Sapindus Trifoliatus. Soap nuts have a remarkable quality, namely that when soaked in water the shells produce saponins, in other words, soap! A few soap nuts placed in a muslin bag or even in a sock tied at the end and placed in the washing machine can be used as an alternative to chemical laundry detergents. For those who suffer from allergic skin conditions (such as eczema) or multiple chemical sensitivity (MCS) they are ideal as they provide a method for washing clothing that is completely free from petrochemicals and fragrances.
Soap nuts are now widely available both on the internet and at health stores. They are relatively cheap to buy and can be re-used, maintaining their effectiveness for around 5 wash loads.