NPT RT-143M 1" x 4" Tile Retro Matte Gray - Material can be cleaned with any mild nonabrasive household cleaning product due to the chemical resistant nature of the glaze. With regard to the durability of the bisque and glaze, this material is suitable for: all vertical applications - residential and commercial, all interior wall, countertop and floor applications, fireplace surround, hearth and firebox, light commercial flooring applications, all exterior wall applications including building facades, swimming pools, fountains, and outdoor kitchens.