Most People Don't realize A diesel engine can run on used deep-fryer oil This by no means is a perfect method, or the best way to do it, just a Way for you to learn an easy way for beginners to get into this. Consider it a first step to living a GREENER life. (this instructable is a continuing WIP so the more we share and learn the more it will be updated, please try to keep the criticism "constructive")
http://www.instructables.com/id/Convert-your-vehicle-to-bio-diesel/