A method for treating the air-fuel mixture to feed to any one internal combustion engine, characterized by the following magnetization steps: - treatment of the fuel present inside any one tank (2) due to at least one immersion container (1), equipped with a plurality of holes (40), placed in proximity to the fuel duct (8) and containing at least one cylindrical container (3), equipped with a plurality of holes (41), in turn adapted to contain a plurality of magnetic elements (5) spaced from each other by the same number of ceramic spacers (6); - treatment and magnetization of the air fed to the internal combustion engine due to at least one pair of magnets (16), placed on the suction duct (17) in proximity to the engine, adapted to provide the air fed to the engine with a charge with sign opposite that provided to the fuel fed to the engine by means of devices b, c, d.