Abstract: An apparatus and a method for cleaning a polishing pad used in a chemical mechanical polishing apparatus are disclosed. In the apparatus, a plurality of brush means is mounted to the bottom surface of either a conditioning head, a slurry delivery arm, or both for operating in-situ or ex-situ in a chemical mechanical polishing process. Each of the plurality of brush means may be formed of a multiplicity of bristles made of a polymeric material that is acid resistant and base resistant. A suitable material is nylon that has sufficient hardness for efficient cleaning of surface grooves in a top surface of the polishing pad. The present invention novel apparatus is efficient in removing particles from the surface grooves before the particles present a serious scratching hazard or otherwise damaging the wafer surface during a CMP polishing process.