Abstract: A method for reducing at production levels sticky, abrasive waste shingles and portions thereof into a reduced shingle material for use of a patch for potholes and cracks and as paving for roads and the like comprises shredding of the shingles to pieces, milling the pieces to particles and granules and impinging the particles and granules with intermittent blasts of compressed air to prevent clogging and sticking and to assist in discharging of the reduced shingle materials. The method may also include the step of spraying water upon the shingles and inside of the apparatus. The apparatus includes an improved hammermill with a compress air manifold with apertures therein for intermittently discharging compressed air which impinges upon the inner chamber of the hammermill and upon the pulverized waste materials. A pressurized water manifold with apertures may also spray the mill chamber of the hammermill with water to prevent clogging or sticking of the hammermill.