1 Gallon of Detergent:
Measure 3 tablespoons borax and 3 tablespoons washing soda into a glass measure. I like to use on with a spout. Mix together well. Using funnel, pour into 1 gallon jug. Add 3 tablespoons soap. Add 4 cups boiling water. Swirl mixture around gently, or mix with a spoon. Then fill to the top with cold water. It will bubble up and it will also be quite runny.
2 half-gallons of Detergent:
*2 half gallon jug directions: Measure 3 tablespoons borax & 3 tablespoons washing soda in a 4 cup pyrex glass measure. Mix. Add 2 cups boiling water. Mix. Add 3 Tablespoons soap. Mix. Divide this mixture evenly into each 1/2 gallon jug,using a funnel. Add 1 more cup of boiling water to each jug. Fill each jug to the top with cold water and gently turn upside down & right side up to combine.
***DO NOT vigorously shake, as people in the comments have been burned when the steam produced too much pressure when they took the lid off.
Use 1/2 cup-1 cup per load depending on how large and how soiled the load is.
It is not a sudsy detergent, and comments in original post say it is fine for HE washers.