Fill a spray bottle with your choice of cleaning solutions. Diluted bleach works well to whiten tubs, as does grease-cutting dish soap mixed with water. There are a number of commercial shower cleaners, as well, that do the trick.
Spray your detergent on the tub and shower's surface and walls. Allow it to sit for at least 10 minutes to allow it to penetrate any stains or grime.
Use an abrasive on trouble spots after you have allowed the cleanser to penetrate. Commercial powders work well, or use salt, boric acid or baking soda. Scrub soiled areas with a sponge or rag, rinsing frequently with a pitcher of water to observe your progress.
Rinse and dry the tub thoroughly when you are satisfied with the tub and shower's whiteness. Drying it after every use cuts down on the incidence of mildew growth.
