Abstract: Method and apparatus for removing excess ceramic slurry from polyurethane foam used as a matrix for ceramic material in manufacturing filters for molten metals such as aluminum. The apparatus comprises a first chamber for retaining a body of polyurethane foam impregnated with a slurry of ceramic material; a second chamber; a slurry-permeable screen between the first and second chambers; and compression means for pressing the polyurethane foam against the screen. By evacuating the second chamber and simultaneously compressing the foam against the screen, slurry is withdrawn from the foam into the second chamber while retaining in the foam an evenly distributed residue of ceramic material.