A handmade liquid soap recipe is available from About.com. Heat 16.5 ounces sunflower oil and 7 ounces coconut oil in a Crock pot. Dissolve 5.5 ounces potassium hydroxide in 16.5 ounces distilled water, and slowly add to the hot oils. Blend the mixture with a stick blender.
After around 30 minutes of blending, the soap mixture starts to thicken. Heat the mixture for 3 to 4 hours, until its texture resembles Vaseline. Mix 40 ounces distilled water into the paste until it dissolves, and leave to cool. Next, neutralize the mixture with borax, and add fragrance. Essential oils work well as fragrances.
For a simpler liquid soap, grate a bar of soap into 4 cups hot water. Stir until the soap dissolves and the mixture thickens. Allow the mixture to cool, and add essential oil for fragrance.