Abstract: A method and apparatus for cleaning vacuum ultraviolet (VUV) optics (e.g., one or more mirrors of a VUV) of a substrate inspection system is disclosed. The cleaning system ionizes or disassociates hydrogen gas in a VUV optics environment to generate hydrogen radicals (e.g., H*) or ions (e.g., H+, H2+, H3+, which remove water or hydrocarbons from the surface of the one or more mirrors. The one or more VUV mirrors may include a reflective material, such as aluminum. The one or more VUV mirrors may have a protective coating to protect the reflective material from any detrimental reaction to the hydrogen radicals or ions. The protective coating may include a noble metal.