How to Remove Rust From a Toilet Bowl

The brown coloration of rust stains bears an unfortunate resemblance to other types of stains and can give people the impression that you maintain unsanitary conditions in your bathroom. It isn't your fault, of course. Rust stains are virtually inevitable in any bathroom and especially one with hard water.

The main problem is iron in the water, which oxidizes to form iron oxide, or rust. It wouldn't be a problem if it just settled on the porcelain surface of your toilet because it would wash off whenever you flush. Unfortunately, it forms a chemical bond that makes it cling to surfaces, and as you probably know by now, that bond is strong enough to resist scrubbing with conventional cleaners. You need an acid to break the bond, and the two acids that homeowners use most often are vinegar and lemon juice.

The 4 to 8 percent concentration of acetic acid in the bottle of distilled white vinegar you probably have in your kitchen cupboard is what gives the vinegar its pungent odor and tangy taste. It's strong enough to do the job, but if you want faster results, use horticultural vinegar, which can have an acetic acid concentration of up to 45 percent. That's a strong acid that should be treated with respect, so if you use it, be sure to wear goggles and protective gloves.

Pour the vinegar directly into your toilet bowl and let it sit for several hours to get rid of stains at the water line and below. To remove the stains around the underside of the rim (where they tend to be darker), make a paste with vinegar and borax or laundry detergent, spread the paste liberally on the stains, and wait for several hours before flushing.

If you want to remove rust stains inside the tank, turn off the water and flush to empty the tank halfway. Then, refill it with vinegar. Wait a few hours before turning the water back on and flushing.

The acid in lemon juice is citric acid, and it's another home remedy for rust removal. It isn't quite as strong as vinegar and works best when you use it full strength, so if you want to use it in the toilet bowl, you should turn off the water and flush to empty the bowl before pouring in the lemon juice.

Perhaps the best way to use lemon juice is to make a paste and spread it directly on the stains. Don't mix it with baking soda, which is alkaline and will react with the acid to form bubbles of carbon dioxide. The fizz is satisfying and looks like it's cleaning, but it won't have much if any effect on rust. Instead, mix the lemon juice with a powder that won't react. If you don't have any borax or powdered laundry detergent, you can use salt as long as you avoid spreading it on metal parts of the toilet. You could even use flour in a pinch.

Although vinegar and lemon juice are both effective rust removers, they may not remove the deepest stains, and you may have to scrub those off. Use a pumice stone for this: it's a volcanic rock that won't scratch the porcelain.

You've probably heard that Coca-Cola can dissolve nails, so it must be able to dissolve rust. It can because it contains phosphoric acid. You can pour it in your bowl or tank, although it probably won't work well as a paste.

Finally, for removing really tough stains, you might want a really tough cleaner. No, not bleach. Bleach will only fix the stains and make them harder to remove. You want a commercial rust and lime remover, such as CLR. It contains not just one but four different acids and will work quickly if you use it according to the instructions on the label.