After each use, rinse the baby bathtub with warm water to remove any soap residue or debris. Fill the tub with warm water and add a small amount of mild baby soap or detergent. Use a soft sponge or cloth to scrub the bathtub gently, paying attention to any areas with stains or grime. Rinse the bathtub thoroughly with clean water to ensure all soap or detergent is removed. Allow the bathtub to air dry completely before storing it or using it again. Periodically, you can also sanitize the baby bathtub by using a diluted bleach solution (follow the manufacturer's instructions) or a baby-safe disinfectant. Rinse thoroughly after sanitizing to remove any remaining cleaning solution.