Bathtubs can become infested with organic materials, like body oils, skin particles, hair and dirt, in addition to the natural buildup of soap and mineral deposits. From time to time, your bathtub can benefit from a good disinfection. Bleach makes a powerful disinfectant, but if you fail to use it properly, it may damage or discolor your bathtub surface.
Bleach is highly corrosive. It can do more damage to your skin than it can do to your bathtub, so always wear rubber gloves when working with household bleach. A white bathtub can benefit from the occasional bleach treatment, but always use it in moderation. Simply pouring undiluted bleach directly onto the bathtub surface may cause the porcelain or other material to become permanently discolored. Bleach has enough strength to work even with heavy dilution.
When Not to Bleach
In some cases, you should avoid bleach altogether. If you have colored tiles and colored grout inside your bathtub, or if the tub itself is pigmented with colors other than white, chlorine bleach may cause the pigments to permanently fade, even when heavily diluted. For any colored bathtub surface, use oxygen bleach instead. Oxygen bleach uses peroxide and soda ash to disinfect, and does not cause colors to fade.
Methods of Bleaching
Your ideal bleaching technique will depend on the type of problem that you hope to resolve. For example, if you just want to remove a particularly difficult stain at the bottom of the tub, dampen a paper towel with bleach and press it against the stain until it fades. If necessary, add more bleach as the paper towel dries. After removing the paper towel, rinse the tub with water. To disinfect the entire tub, mix half bleach and half water in a spray bottle and spray the tub surface. Scrub with a firm brush and rinse with hot water.
If you wish to avoid bleach products altogether, the green cleaning website Re-Nest recommends treating the tub with grapefruit and salt. The salt contains chloride, one of the ingredients in the bleach compound, and grapefruit contains citric acid, which also cleans and disinfects. Cut the grapefruit in half, sprinkle salt over it and scrub your entire tub to clean and disinfect. Rinse with water and call it a day.