Abstract: An elongated cylindrical housing is arranged to be mounted adjacent to and parallel with the surface of a moving abrasive member and has a row of ports establishing communication between the interior of the housing and its exterior. An elongated cylindrical core member is rotatably supported in the housing and has a spiral groove in its surface of a selected width and pitch such that a small number of ports are exposed to the groove at a time to form a narrow jet. Fluid under pressure is supplied to the groove and upon rotation of the core member the jet of fluid travels across the surface of the moving abrasive member to clean it. A cam is provided in the present apparatus to reciprocate the housing in its longitudinal dimension through a distance approximately equal to the spacing of the ports so that the surface of the abrasive member between the ports is also cleaned.