A while back I bought some soap nuts. I've used them in my washing machine as a laundry cleaner* but knew they were capable of so much more....
* Tie 4-6 soap nut shells in a muslin bag (provided with most soap nuts orders) and put it in the washing machine load at a desired temperature. You can use the same pouch for 4 to 6 loads of laundry. When the shells become grayish and mushy, they are ready to be replaced and added to your compost. My next step in replacing commercial products is to use them as a dishwashing liquid.
Dishwashing Liquid Recipe
To make the liquid, boil 100g of soap nuts in 12 cups of water for approximately 30 minutes. Cool the liquid, remove the shells, and your liquid soap is ready! Storing the liquid in an air tight container helps it to keep longer. Because there are no added chemicals in soap nuts liquid, it can go bad after some time, depending on the storing conditions. You can use this liquid for washing the dishes or even use 3 tbsp for a large load of laundry.
This liquid can then be used as castilles soap in other recipes such as towards sutainabilities recipe here or melissas here