The basic ingredients for laundry soap are bar soap, borax and washing soda. Baking soda, oxygen based bleach and scented crystals such as Purex Crystals can also be added to the mix.
The first step is grating one bar of soap, either with a cheese grater, box grater or food processor. The grated soap gets mixed with one box of borax and one cup of washing soda. Borax is a mineral made of boron, oxygen and water. Washing soda is sodium carbonate, also known as soda ash. It's simply made of salt and natural limestone. You can also add a box of baking soda to remove smells, a container of oxygen based bleach or a container of scented crystals. Everything gets mixed together and stored in an airtight container. Use one to two tablespoons per load.
The process is slightly different for making liquid detergent. In this case, the bar soap still gets shaved down. This gets added gradually to four cups of boiling water, stirring the mixture until it's dissolved. In a larger container add three gallons of warm water, one cup of washing soda and a half cup of borax, stirring until thoroughly mixed. The mixture needs to set for a minimum of twenty four hours, at which time it should resemble the consistency of store-bought liquid laundry detergent. Use one cup of liquid per load.