Use an enamel roasting pan (do not use aluminum). 1 can lye (I use a glass coffee pot to mix lye and water in) 10 c. grease (I use cheap white lard) 3 pts. water 1/2 c. Borax 1/2 c. ammonia
Melt grease and let cool. Pour water on lye and let cool (stirring to dissolve). Add Borax to lye water; stir until dissolved. Add this to the grease and stir 7 minutes. Add ammonia and stir 3 minutes longer. The more you stir it the whiter it grows. Pour up into a wax paper lined box or soap molds. Let set overnight. Turn out and cut into bars. Set aside and cure for 4 weeks. I use mine to get stains out of garments and on collars and dirty socks.
NOTE: Pringle cans make good soap molds. Cut the top and bottom out and place a plastic lid on the bottom. After it sets, take the bottom off and push the soap out and slice.