Forgive the students at Sinclair Community College if they get the munchies when they pass the tractors that cut grass, blow leaves or sweep snow on campus: Oil that once cooked french fries and onion rings is being used to power the vehicles. Students have begun making biodiesel fuel by converting used cooking oil from the dining hall. Biodiesel saves the school a little money on gasoline, gives the students lessons in engineering and chemistry, and removes oil from the waste stream.