Sciencemadness Discussion Board

Best way to dissolve bathroom mineral stains?

Jeeves225 - 2-6-2023 at 03:10

Hi friends,

As like most of you I own a bathroom. My bathroom has mineral stains on the tiling, which I'm trying to get rid of:



Now I've tried several approaches: consumer grade cleaning vinegar (longer exposures, up to an hour), 10% hydrochloric acid (only a few minutes, this dissolved the grout however), bathroom cleaner which advertised lime-removing capabilities, and also bleach.

Yet much to my dismay, the mineral stains remain. Are there any approaches you could think of that would remove these stains effectively? Local application of a concentrated acid for example? If I could apply it on a paper towel and use that to clean the tiles, that would work for me. I would aim not to dissolve the grout.

Look forward to hear your thoughts.


violet sin - 2-6-2023 at 07:24

I'd suggest one of my favorites, sulfamic acid. You can find it at most hardware stores, as a tile de-hazer. I've used it for electroplating and other experiments.

should try it myself, I do have a window that got over spray from the sprinkler, then sunbaked on. I couldn't get that stuff off with things like vinegar or CLR cleaner, it only took off the easy bits and left anything remotely stubborn.

Maybe I'll mix up a batch this evening and try it out. The stuff is about 12$ for a one pound jar at ace hardware, easy to get. If I can find the jar I have I'll give it a go.

Lionel Spanner - 2-6-2023 at 07:27

It might be worth trying "active oxygen" type laundry powder wetted with water. The so-called "active oxygen" is sodium percarbonate, which, when dissolved, can be a very effective cleaning agent.

Bedlasky - 2-6-2023 at 07:32

Try EDTA or pyrophosphate, they form soluble complexes (assuming that these stains containing some metal like Ca, Mg...).

teodor - 2-6-2023 at 07:43

Sulfates are problem, I used pumice powder applied on a polishing disk with a drill ... I am not sure about a chemical way, I remember I tried 5-7 different chemicals. Probably I did't tried calgon, I am not sure about its effect on sulfates but wanted to try.

[Edited on 2-6-2023 by teodor]

Bedlasky - 2-6-2023 at 09:42

Sulfates are soluble in EDTA. I once did titration of PbSO4, I dissolved it in Mg-EDTA complex (Pb displace Mg in complex, Mg is than titrated with EDTA). But dissolving was painfuly slow. Hot solution will probably do better job.

clearly_not_atara - 2-6-2023 at 10:24

The challenge is not to attack the grout, too. I would usually try Soft Scrub (long-chain alkyl benzenesulfonates) first before moving on to anything reactive.

Citric acid complexes calcium. Since that is a very common culprit, maybe try that.

violet sin - 2-6-2023 at 13:24

A cheap pumice stone deff works on porcelain
https://www.walmart.com/ip/Pumie-Scouring-Stick-non-toxic-re...

It's not chemical, but you also don't need any special tools. They wear away quick some times. In store it was under 2$

Edit... Spelling

[Edited on 2-6-2023 by violet sin]

Herr Haber - 2-6-2023 at 14:56

Quote: Originally posted by violet sin  
I'd suggest one of my favorites, sulfamic acid.


"While reading a forum on chemistry, I came upon the statement 'sulfamic acid acts upon bathroom stains." I was getting tired of reading such absurd stuff and I determined to see what this meant.
[snip]
The spirit of adventure was upon me. Having sulfamic and a dirty glass curtain in my shower, I had only to learn what the words 'act upon' meant. Then, the statement, 'sulfamic acid acts upon bathroom stains' would be something more than mere words."

I'll stop with the plagiarism here...
It did not act upon the sponge, nor my fingers but I was reminded that it was not very soluble.

Other than that, there's a very big smiley on my bathroom glass curtain so it worked quite well :)

Will continue tomorrow while in the shower see if I can break another piece of glassware there.

[Edited on 2-6-2023 by Herr Haber]

j_sum1 - 2-6-2023 at 17:37

CLR is 7% lactic acid plus a surfactant FWIW.

Jeeves225 - 3-6-2023 at 05:03

Thanks for all your ideas. I'm now trying Vanish Oxy detergent per Lionel Spanner's recommendation as that what I had at home. I'll report back on how that's working, and otherwise I'll definitely see about getting my hands on some sulfamic acid. :)

Jeeves225 - 5-7-2023 at 02:50

So, I've tried several methods. I went to the hardware store and bought two lime scale removers, one being normal strength (which included a small amount of sulfamic acid) and one being '3x' strength, which only contained a higher concentration of phosphoric acid. These worked wonders on some of the scale on e.g. the shower head but most of the tile was unaffected.

I then tried some car polishing compound on the tile, and all mineral stains disappeared after only a brief amount of scrubbing. I'll go ahead and proceed with this approach to remove the scale on all the tile.

Fantasma4500 - 6-9-2023 at 08:21

best bet ive found is to get an electric drill, put in a steel brush, then ontop of that you put a steel sponge- used to clean stuff up in kitchen, and then go at it with that, that will take off the worst
after that i advice phosphoric acid as it wont evaporate and will only concentrate further as the water evaporates, maybe some gelled up acetic acid, xanthan gum?

WGTR - 7-9-2023 at 01:44

Do you have city water, or is it from a private well? In our area some wells have gypsum, which is pretty hard to remove with anything other than mechanical means. It is very slightly water soluble. This is how it deposits in the first place. Once it builds up over a long time it is a big chore to remove. I think boiling concentrated sulfuric acid dissolves it…

The best option is preventative. There are “daily shower cleaning” sprays that basically leave a film that keeps hard water deposits from sticking. Then the surfaces are easy to keep clean.

Sachingare - 24-11-2023 at 04:07

Are you completely sure those are stains? It kinda looks like the originally smooth coating is damaged.