"Open-grain" wood structures such as oak, mahogany, and ash are difficult to fill with clear finish. Aqua Coat Clear Grain Filler levels wood pores for a smoother finish. It can be applied with a small rubber squeegee, an old credit card, or a buffing pad. A popular method is to apply it much like paste wax with a circular motion, working it into the grain. Apply 1 to 2 coats as needed of Aqua Coat water-based Grain Filler. It dries completely clear, but any excess should be removed before drying. Any remaining residue can be sanded off.