Cleaning the sand blocks or sponges seems a difficult task at first, but it’s not. First, try removing some debris with your hand, or use a cloth. Then soak it into the water, now some blocks will float, and debris will float-away without using any detergent or rubbing. Other blocks, mostly sponges, require using warm water, detergent, and hand rubbing to wash it off. And finally, dry the blocks well, and it’s ready to use again.