Although some toilets are made with a stain-resistant finish, the bowl is still at risk of staining. The minerals in standing water can discolor the porcelain. Brown- and rust-colored rings can be a particular problem in areas that have mineral-rich water, also known as hard water. If allowed to build, such stains require strongly acidic cleansers to remove. These products can slowly erode the porcelain, not to mention the immediate damage they can do to the skin, eyes, nose and throat.
It's worthwhile, then, to practice preventive maintenance. First, make "flush" a family rule. Also, make a simple routine part of your weekly cleaning: Sprinkle the toilet with cup of baking soda. Let it sit for 30 minutes, then spray or squirt with vinegar (a mild acid) to moisten. Scrub with a bowl brush and flush away [source: Niagara County].
Minerals contribute to another common bathroom cleaning problem. Read on to learn how baking soda can clean up the scum of the earth.