Acrylic tubs shine and sparkle when clean, but a mild stain can make your tub appear dingy. Since acrylic is a delicate material, traditional cleaning methods and solutions may not be the best for your tub. Paint thinners, steel wool and acetone treatments, for example, only further damage your acrylic bathtub. Gentle cleansers like dish liquid soap, or even ammonia-based tub cleansers, work best for acrylic tubs.
Fill a spray bottle with an ammonia-based cleanser. The spray will allow the product to cover more space.
Spray the cleanser on the entire surface of the tub, and allow it to sit on the surface for 5 minutes so that the stain has a chance to break up or soften. The gentle effect of ammonia-based products makes them viable tub cleansers
Scrub the tub in a circular motion with a wash cloth moistened with water. The scrubbing must be firm, and the circles must be small, vigorous circles.
Rinse the surface with warm water, and gently scrub in small circles until you no longer see a stain.
Perform the scrub procedure again with dish liquid on the stain if you still see remnants of a strong stain. The dish liquid will penetrate to break up the remainder of the stain without damaging the surface.
You can find acrylic tub cleansers in hardware and grocery stores in the cleaning aisles.