I've had tenants that I guess used the toilet but never flushed. Anyways, I'm unable to remove the yellow/brown deposits from the bowl, they seem to be really hard rock-like formations - I've ended up destroying the bristles on the brush while scrubbing.

What could I use to remove these deposits?

3 Answers 3


It's essentially an external kidney stone.

You can use various types of acid - sometimes a alternating approach of chlorine bleach (by itself) to kill the biofilm that's exposed and acid (by itself) to remove the "more or less limestone" is beneficial. The biofilm can prevent or slow the acid from getting to the underlying stony material, and it tends to have a layered structure.

Vinegar works, but slowly. Citric acid should work better (it's a stronger acid) but can be harder to find. Muriatic (aka hydrochloric) makes me a bit uncomfortable, personally, but there are commercial toilet cleaners that contain it. Be sure to use gloves and goggles if you opt for the stronger stuff.

  • Citric acid can be bought as a sugar-like solid substance quite easily. One way how to apply it is to cover the "stone" with a layer of the acid and than spray it with water using a spray bottle; this way you create a very strong solution.
    – yo'
    Oct 26, 2015 at 18:45

There is debate over using Muraitic Acid (http://www.homedepot.com/p/Klean-Strip-1-gal-Green-Muriatic-Acid-GKGM75006/202690263) which is typically what I've seen for intense deposit build ups in toilets.

There is apparently a recommendation from someone to use a Pumice stone and hand scrub it.

  • 1
    A pumice stone may indeed be able to remove deposit buildup. I use this all the time to remove the calcium build up that occurs at the waterline over time. Be aware that sometimes a yellow brown stain in a toilet may be due to excess iron in the water. In some cases iron stains may actually get into the porcelain and not be easily removed using a pumice stone. In that case is may be easier to just replace the toilet stool.
    – Michael Karas
    Oct 23, 2015 at 13:47
  • 1
    Scrubbing with abrasives, wire brushes, etc will abrade the surface of the porcelain, and will make it nearly impossible to clean in the future. The porcelain's clean, factory finish acts almost like a non-stick surface in cookware. Once it's scratched and stained, it may just be time to replace. Oct 23, 2015 at 14:20
  • I agree with the sentiments on abrasive scrubbing on porcelain, doubly so since I haven't seen pumice stones with a long handle. My recommendation is the acid and let it sit in the water for a few minutes then flush/normal bristle brush and see how it looks then repeat as necessary. I would not recommend leaving the acid in the bowl undiluted or for an extended period. Oct 23, 2015 at 14:29

Yeah, removing those type of stains can be difficult (I've replaced toilets due to customers not being able to remove them!). The fastest (but not the easiest) solution I've found is not the most pleasant. After bailing out most of the water from the bowl (leave some standing water to facilitate removal of stain) don some latex or protective gloves. Purchase a pumice stone usually sold at hardware stores. If the stain is extensive or thick it would be wise to have more than one available. Start scrubbing. The pumice (igneous lava rock) scrapes and erodes the encrusted stain without damaging the porcelain layer of the toilet. The pumice is light-weight and will seemingly disappear as it is pressed onto the surface. Usually two pieces will completely remove the problem. here's the link: http://www.amazon.com/Pumice-HDW-12-Pumie-Scouring-Stick/dp/B0082D0FCA/ref=sr_1_7?ie=UTF8&qid=1445615917&sr=8-7&keywords=pumice+stone

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