If a diesel car or truck can run on well filtered fry oil, why go through the trouble of converting it to biodiesel? The chemicals used to convert the oil are nasty and it is something I do not want to deal with. From what I have read you can have a small tank of straight dieasel in your trunk for starting up and heating the fry oil. You then turn a valve which stops the flow of diesel and starts the flow of the fry oil. You then do the opposite when it is time to stop the engine to clear the engine of the oil so it doesn't solidify and clog your engine. This seems to make a lot of sense to me and keeps me free of chemicals more toxic than the original deisel I am trying to get away from or at least use less of. What am I missing?