Methods for converting motor oil into fuel generally include forming a conversion mixture of an alcohol and a base, and adding the conversion mixture to motor oil, to form a reaction mixture. The methods can also include adding a high nitrate compound and an amino acid to the reaction mixture and ozonizing the reaction mixture. The result of the methods can include a three phase system in which the bottom phase is asphalt oil, the middle phase is diesel fuel or jet fuel, and the top phase is sulfuric acid. The three phases can be separated to obtain the final diesel fuel or jet fuel product.