Melt the fat in a large iron or enamel pan (do not use aluminum).
When it is melted there should be 6 3/4 pints.
Set it aside to cool at 80 degrees F.
Combine one (13 ounce) can of lye with 5 cups of water in an enamel pan and stir slowly with a long, wooden paddle until the lye is dissolved.
Along paddle is necessary to keep the splashes from burning the hands.
Cool to 70 degrees F.
Add the lye water gradually to the fat, stirring slowly with the paddle for at least 10 minutes.
Continue stirring until mixture is creamy, then add the borax, sugar and ammonia.
Mix well and pour into shallow pans or molds.