Some friends of mine from ws toured the country 2 years ago in a grease powered bus. Started on deisel and once it warmed up they switched to grease. smelled like a french fry going down the road. They would stop at any fast food place and ask for old grease and filter it before going into the tank. From winston to Boston then west to cali and back through the southern states to florida then home. It was called the "phychic revolution."