Shred a bar of Fels Naptha soap ( most stores sell it in their cleaning aisle, not with bath products). Boil that until all pieces are liquefied, about 5 min. Add a half cup of Borax and a half cup of washing soda, boil again until everything is dissolved. Pour into a large bucket that has about 2 gallons of warm water in it and stir. Let sit for 24 hours. What you will have is a thick, slippery product. I have my husband mix this with his drill to get it really mixed but you don't have to, just stir really well with a big spoon. This is the concentrated product. I no longer measure how much of this concentrated soap product I add to the water in my saved detergent bottles, I just estimate. I probably do about 20 % product and 80 % water. If you don't mix it really well (like with the drill), there will be some separation as it sits and you will have to shake before each use. For the amount of money I have saved over the years I don't mind shaking.The 3 products needed to make this are dirt cheap! I have a family of five. we do at least 2 loads of laundry a day. With this recipe, I only have to make the detergent once every few months. The boxes of washing soda and borax last me about 2 years. The Fels Naptha I have to buy a bar (99 cents) each time I make it.