If you’re referring to a B-12 Chemtool fuel additive, no—there are no true oxygen sensor cleaners that are safe to put through your engine. While some people choose to remove them and use a wire brush or an aerosol cleaner to remove other types of deposits, we do not recommend trying to clean O2 sensors. We feel their function is too critical to risk damaging the sensors and possibly (and erroneously) altering the air-fuel mixture.