O-Cel-O Stay Large Sponge contains a patented antimicrobial that helps the sponge resist bacterial odors, killing odor-causing germs & bacteria in the sponge. Sponge resists staining & crumbling from mildew & frequent use. Ideal for washing woodwork, cars, boats & household cleaning tasks. Highly absorbent, durable sponge is made of cellulose that is derived from wood pulp, a renewable resource.