Method for selectively oxidizing the dielectric surface of a substrate surface comprising a dielectric surface and a metal surface are discussed. Method for cleaning a substrate surface comprising a dielectric surface and a metal surface are also discussed. The disclosed methods oxidize the dielectric surface and/or clean the substrate surface using a plasma generated from hydrogen gas and oxygen gas. The disclosed method may be performed in a single step without the use of separate competing oxidation and reduction reactions. The disclosed methods may be performed at a constant temperature and/or within a single processing chamber.