The CleverSpa Clever Sponge is the clever eco-friendly way to clean your Hot Tub. Just add water to your CleverSpa sponge and clean your surface as normal, no need for any chemicals or detergents. Watch as dirt, stubborn stains, grease and grime are easily wiped away! The CleverSpa Sponge is chemical free, so it is safe to use even when your hot tub is full of water, saving both time and water as you don't need to drain your tub in order to give it a thorough clean!