CounterArt Sea Glass Absorbent Coasters, Set of 4 Set of 4 absorbent coasters with attractive design marries artistic form with high function Coasters are natural stoneware with decorative transfer print Each coaster has a durable cork backing to protect countertops and furniture To remove stains, soak coaster in 1 part household bleach and 3 parts water until stain lifts, then rinse and air dry Holders available; look for counterart wood coaster holds ( sold separately)