Marflo’s advanced synthetic block won’t cause swirls, scratches, or marrings, works perfectly with most lubricants, and never leaves markings or scratches on your vehicle’s paintwork. The froth sponge block is reusable, washable.Helps lift off dirt, dust, tar, water spots, overspray, bird droppings, and more for a smooth glass surface, makes the froth sponge block easier and faster, can be used for glass deep cleaning and in a wash bucket for added scrubbing effect.