Beans-Shaped Bottle Cleaning Sponge (Set of 2) - Cleaning reusable water bottles and plastic bottles has never been easier. Simply drop the sponges into the bottle, fill it with water and a dash of detergent, close the cap, and shake it up! Weighted balls inside the beans allows for quick cleaning, all it takes is a few shakes. - An ingenious and effortless way to clean the inside of bottles and other containers with narrow openings. These bean-shaped sponges contain alumina ceramic balls inside, which add a heft--allowing for a truly impressive kind of clean. It's really that easy. String can be tied to sponge at hole on top to enable pulling dropped sponge through extra narrow openings.