Made of certified organic bamboo fiber and cornstarch, the"Colorblock" set of four coasters designed by Poketo are 100% biodegradable, free of melamine and plastic. Toss these on the table alongside our bamboo dishes, bowls, and serve-ware to complete the sustainable scene. Made from bamboo fiber cornstarch and printed with food-grade ink. Non-toxic and Compostable. Do not submerge or soak in water. Towel dry or vertically air dry and store in a cool, dry place. Do not microwave. Dishwasher safe. Slight color variations are a natural by-product of the bamboo fiber. Measures 3.5 in.