300 g (10 oz) bars of soap
1.5 cup washing soda
7.5 ltr water
*10-ltr pot is helpful
Boil 1.5 liter of water in a 10-liter pot. Grate the soap and put it in the pot, stirring to dissolve. Slowly add in the 1.5 cup of washing soda while stirring until it is completely dissolved. Turn off the heat before it overflows. Remove from heat and put it on the floor. Add in the remaining 6 liters of water into the pot and stir. Cover and let the soap sit for about 24 hours and it will gel. It will look like an opaque liquid with some soft lumps. Stir and bottle it. Shake and use 1/4 cup per load.
Remember that washing soda is caustic, so wash utensils, etc. thoroughly with soap and water after contact with it.
For extra greasy dishes, rinse it in EM (efficient microorganisms) before washing them with the dish detergent so that you won't waste the detergent unnecessarily.
Optional: add 1-1.5 oz of essential oil or fragrance oil if desired