An improved method and apparatus for removing accumulated films from processing equipment. Accumulated films are removed without disassembling the equipment and by introducing an interhalogen gas into the chamber where it reacts with the accumulated films while only slightly or not reacting at all with the processing chamber or its internal parts. The interhalogens and its products formed are volatile and are easily removed by a vacuum. The noncorrosive reaction takes place without needing a plasma and unlike HCl, the reaction take place from about room temperature to 300.degree. C.