The best way to clean toilet stains from tough mineral buildup is with lemon juice or any source of citric acid. Spray on the lemon juice and leave it overnight. Then spay on another light layer and wait a few minutes before scrubbing your toilet. Flush to rinse away the stain.
Citric acid
More importantly, it's probably even more effective than vinegar for getting rid of that brown stain in the toilet. Simply pour a kettle of almost boiling water into the bowl, follow up with 250ml of citric acid, and leave it for some hours – preferably overnight. The next day, scrub and flush.
Brown stains can also come from iron bacteria, manganese bacteria or sulfur bacteria. These organisms grow in soil or shallow groundwater with high iron, manganese or sulfur concentrations. Water containing these bacteria leaves behind slimy brown rust deposits in plumbing fixtures and toilets.
There are a few ways to restore your porcelain tile after you've come across a stain. You can try tackling the spot with some hydrogen peroxide or by using a steam cleaner. For more difficult stains, consider trying diluted muriatic acid, an industrial-strength solution professionals have been using for decades.
The brown stain is from a large amount of iron in your water. It is closely related to simple rust that you see on metal, which is iron oxide. Your water probably comes from groundwater that filtered through rocks containing iron-rich minerals on its way to the well.
A much better solution is to use some WD-40 Multi-Use Product. Most people don't know that WD-40 can solve many of their household cleaning needs quickly and easily. When cleaning a toilet bowl, WD-40 works by softening the rust and lime deposits, so they can be easily wiped away. You don't need to use much of it.
Green or brown stains in the toilet usually indicate lime buildup. Lime scale forms as hard water evaporates and leaves a mineral buildup behind.
Another popular method to remove limescale from your toilet is to use vinegar and baking soda. Pour about one cup of white vinegar into the toilet bowl, followed by about one cup of baking soda, then let it rest for around 10 minutes.
The solvents in WD-40 help dissolve gunk and lime in your toilet. Spray WD-40 in your toilet bowl and leave it for one to two minutes. Then, use a toilet brush to help scrub away the grime. Because it's so effective, there's no need to saturate your toilet—a little goes a long way.
Vinegar and baking soda produce that oh-so-familiar chemical reaction that powers through buildup and loosens tough stains. While it might seem like it's chewing its way through grime, it's not powerful enough to damage the porcelain finish of the toilet bowl.
Porcelain is a highly durable material for dental restorations, but it is not entirely indestructible. Stains will not penetrate the surface of quality porcelain restorations unless the porcelain has been damaged by: Highly abrasive toothpastes that wear away the outer glaze of the porcelain.
Sprinkle your baking soda (it doesn't need to be an exact amount, just coat the bowl) around the bowl and watch as that chemical reaction sizzles. Swish that solution around using the toilet brush and then let it sit for about 15 minutes. If the stains are still visible use the wet pumice stone and flush.
Add about 1 cup of baking soda to the toilet bowl, then add another 1 to 2 cups of vinegar. You should see and hear some fizzing action—this means that it's working! Let the solution sit and fizz for about ten minutes.
Grab some gloves and use a Magic Eraser to go to town on toilet bowl stains. Some users even recommend cutting a piece off and letting it dissolve the bowl to remove that unsightly ring all on its own.
Steel wool scrub
Since steel wool is such an abrasive product, you can either use it alone or in addition to borax + vinegar +/or baking soda for better results. 0000-grade steel wool is recommended as it's less likely to scratch up the inside of a porcelain toilet.
For white porcelain only, bleach can be used to remove stains; never use chlorine bleach in colored or vintage porcelain, as it can damage the finish. For both white and colored porcelain, liquid oxygen bleach (such as hydrogen peroxide) is a good alternative.
Though popular for being gentler alternatives to harsh chemical cleaners, baking soda, Borax, and even salt can harm the finish of your porcelain fixtures. As gentle as they are, these compounds are still abrasive and will scratch your finish, especially with regular use.
Firing spots are brown or black color defects clearly visible, dark bullet holes on the outside of the porcelain. Please do not confuse them with the dark brown bleeding iron spots which originate in the raw material.