Abstract: A system and method for treating a waxed fiber paper product with a high wax content to remove a substantial portion of the wax content includes the pulping of the wax paper fiber at an elevated temperature in excess of the melting temperature of the wax to separate a pulp fraction and to form an emulsion of water and molten wax. The pulp fraction is separated from the emulsion by filtering in a reverse pressure screen in which a finely perforated screen defines a high pressure side and a low pressure side, and a major portion of the water/emulsion is removed from the suspension through the screen perforations leading from the high pressure side to the low pressure side, in which a rotor and foil arrangement within the reverse screen is operated under such conditions that the suspension at the high pressure side of the screen is maintained in a constant fluidized condition.