Weathered Membrane Cleaner is used to clean both new and in-service WeatherBond RBR EPDM membrane and WeatherBond PRO™ TPO membrane prior to the seaming process. It helps to loosen and remove dirt and other contaminants from the surface of the EPDM and TPO membranes and leaves a suitable surface for welding or the subsequent application of primer. Do not use Weathered Membrane Cleaner on PVC membranes instead use PVC Membrane Cleaner. Weathered Membrane Cleaner should be used when preparing EPDM membranes for application of primer, adhesives, Pre-Applied Seam Tape and flashing.