I was reading about how to make my own bio-diesel at this wonderful website and was blown away when they said that one of the by-products of the process was soap. You take used deep-fryer grease and mix it with some chemicals and, viola, soap and diesel fuel.
What a payback! Not only do I get the fuel I need to run my vehicle but I also receive for my effort an unlimited supply of hygeine products.
I could even sell the soap and recoup on my expenses. I already have a name for it…
Let me know if your interested, I may be taking pre-orders soon!