5 liters olive oil, old or new. Add 1 kilo caustic soda dissolved in water, add more water. Total amount of water: 5 liters. Stir for one hour. Pour into a form. Let sit over night. Cut. Let sit in a shady place a couple wks. The longer you wait the better the consistency of the soap. If you want a scent, add just before pouring up.
Contrary to what the pictures below illustrates, the caustic soda is very corrosive, and protective clothing, especially gloves and eye protection, is a very good idea. Click below to start slide show.