Abstract: A method and apparatus for masking a part during a multi-step process including a blasting process using abrasive media for etching or cleaning a part. In each step of the multi-step process, the workpiece and mask are aligned together by pins extending from a supporting surface of the apparatus. The pins have a lower surface configured to hold the workpiece and an upper part or portion of a triangular cross section to provide line contact with the walls of apertures in the mask and part. The triangular configuration keeps the mask aligned with the workpiece while at the same time allowing air to pass through the apertures. After the abrasive blasting process, a stream of compressed air is applied to the bottom of the part and mask to cause the mask to move or flutter up and down relative to the surface of the part.