Build-Up Blocker (Mask) 120 MLA physician formulated scalp mask made with natural ingredients that dissolves pore clogging oil and product build up with a gentle exfoliation of the scalp. Clinically shown to visibly improve dryness and remove dirt and product build up. Ingredients Section dry or damp hair with the tip of the tube and apply mask directly to the scalp using enough to lightly cover the scalp. Next, lightly massage into the scalp with fingertips and leave in for 3 to