Embodiments of the invention generally provide a method and apparatus for processing a substrate in an electrochemical mechanical planarizing system. In one embodiment, a contact assembly for electrochemically processing a substrate includes a housing having a ball disposed in a passage formed through the housing. The ball is adapted to extend partially from the housing to contact the substrate during processing. The housing includes a fluid inlet that is positioned to cause fluid, entering the housing through the inlet, to sweep the entire passage. In another embodiment, a method for electrochemically processing includes flowing a processing fluid through a passage retaining a conductive element. The flow sweeps the entire passage of the housing. A first electrical bias is applied to the conductive element in contact with the substrate relative an electrode electrically coupled to the substrate by the processing fluid. After the substrate is separated from the conductive element, flow of processing fluid is continued through the passage past the conductive element.