This 8.5" brush is designed to help reach the bottom of taller containers, like bottles and jars. The bristles are made of coconut fiber with a bamboo handle. Metal spine holding the bristles is not compostable. Pull bristles out with pliers to compost. Pull or saw metal spine off of handle to compost the rest of the handle. Hang your brush, or store in a jar bristle side down, to keep water from pooling on the handle.