Scum bug oil-absorbing sponge absorbs 40x its weight in oil and pollen. When placed in a clean pool or spa, the Scum bug improves filtration and helps to eliminate the formation of a scum line. Place the Scum bug in your pool's skimmer or free-float in your spa. When 1 side is scummy, flip it over. When saturated, squeeze out, clean and reuse.