Discoloured shower door

My shower door has slowly built-up this limescale-like coating over the past 5 years and it does not seem to respond to any attempt to remove it.

It is far more prevalent on the door nearest the shower outlet so it would seem to be simple limescale. However, we have a water softener so the carbonate content of the water should be very low indeed. Also, I have tried using limescale treatment chemicals and they don't work, so this would appear to be something different.

Any suggestions please - or am I wrong and this is ordinary limescale and I'm not treating it properly?

UPDATE: Over 3 years later and I am yet to find a practical answer to this problem. However, I have an update that may be of interest.

On the advice of a couple of the answers, I have finally tried to use steel wool. I can report that
1. This does NOT scratch the glass and
2. It DOES abrade the scale build-up - albeit requiring FAR too much time and effort to be practical.

About 10 minutes of polishing removed around 20% of the scale in 6 square inches of the glass. Enough to see that an effect was being achieved - but also to tell me that a better method is needed. I wasn't using any liquid cleaner, just dry steel wool. Another test beckons....

  • Hi @lefty did you manage to get rid of the limescale? did the caustic soda solution work?
    – Michael Le
    Commented Nov 29, 2018 at 11:35
  • @MichaelLe No, it didn't. I tried a few different things but gave up when none of them worked.
    – Lefty
    Commented Dec 9, 2018 at 22:39
  • It would be useful for others if you added a list of what you tried that didn't work.
    – piojo
    Commented Jan 3, 2020 at 4:37
  • 1
    @piojo Yes, good idea. I will have to do that when I get a chance. It has been 4 years, so it will take some thinking about...
    – Lefty
    Commented Jan 3, 2020 at 8:02
  • @Lefty Yeah, the question just popped up for some reason, and I got to wondering :)
    – piojo
    Commented Jan 3, 2020 at 8:08

15 Answers 15


You can try stronger chemicals to remove the build-up of "lime" (most likely calcium carbonate). In any case, be sure the chemical stays in contact with scale for at least a few hours; use wet paper towels or a chemical gel that adheres to the glass. See some suggestions on how to remove it.

Note that the following will damage marble, aluminum and other surface. In rough order of efficacy and of hazard to materials and health:

  1. Vinegar and/or citric acid (sour salt) are safe first steps, but takes a long while.

  2. CLR is a commercial product with gluconic and lactic acid that you may have tried. Again, keep it in contact long enough to work.

  3. Toilet-bowel cleaner with about 10% hydrochloric acid is hazardous to eyes, skin and mucous membranes, and will rapidly etch marble and some metal surfaces, but could be used over small areas.

Finally, try elbow-grease: rub with an abrasive paste that is softer than glass, such as Bon Ami powdered cleaner. Your experiment at scraping off the lime shows that this should work.

  • Thanks for this. So far we've tried various supermarket-level chemicals but they seemed totally ineffective. We've also tried spraying vinegar on it but that was equally ineffective. I like the idea of paper towels - I think that may be the answer to getting it to stay in contact longer. I also think I may have a bottle of ceramic-hob cleaner around somewhere - I assume that's similar to your "Bon Ami" - it's a very fine abrasive with some chemical additives that help to break down the deposits.
    – Lefty
    Commented Dec 20, 2015 at 20:47
  • I've just tried the abrasive, it's called "Hob Brite". It's just fine abrasive with some surfactants. I did a small area and rinsed it - so won't be able to see how effective that was until it dries. Then put some "Lime Lite" on a small area, that's a gel so it has stayed where I put it pretty well. I also soaked a small piece of paper towel in the same product and left that. Will report back after a long-enough wait to see if there is any effect whatsoever.
    – Lefty
    Commented Dec 20, 2015 at 21:07
  • Ceramics tend to be harder than glass. Bon Ami contains feldspar as abrasive, about as hard as glass (both are listed as ~6 on the Mohs scale). Check that the Hob Brite does not scratch the glass. BTW, even small scratches in tempered doors can lead to shattering. Commented Dec 20, 2015 at 23:40
  • UPDATE. The Limelite was totally ineffective even though it was left to activate for many hours. The paper towel did not help. Am currently testing another chemical based upon hydrochloric acid.
    – Lefty
    Commented Dec 22, 2015 at 23:27
  • 1
    if vinegar doesn't remove anything than it is not limescale. And if it is not limescale even stronger acids to remove limescale wil not remove it.
    – miracle173
    Commented Dec 26, 2015 at 6:49

Know thy enemy

What you are up against, is most likely a bildup of lime, PLUS fatty residue that splashes on the glass when you shower, enhanced in stubbornness by additional compounds from your soap or shampoo. (Perhaps the bildup started when changing products, e. g. Started using an anti-dandruff shampoo that contains selenium silicate )

The end result is that the lime ends up encapsulated and mixed with fatty compounds and that makes it harder for acids to dissolve as they normally do.

Acids may seem like a good solution

Someone suggested phosphoric acid that is probably the worse idea since phosphoric acid is the only acid that attacks glass.

Abrasives too

The pumice stone up there is a good idea however it is still an abrasive solution to a problem best handled by solvents.

Now, acids will not work on this residues so, my advice is to head over to the other end of the pH scale.

The other end of the pH scale

What you need is a strong base, Sodium Hydroxide being the most chemically reactive substance that you can get your hands on.

It is sold as an oven cleaner on most supermaekts, under the generic name caustic soda. It is also sold as a rooter for clogged drains since it is specially adept at dissolving hair.

label on oven cleaner generic caustic soda

Now days, most of this products come in a diluted form to be applied as atomized spray or aerosol foam, however I would recommend going medieval on your lime and apply full strength with prejudice. So be sure and get the real thing which should be a viscous off-white liquid with the same consistency as egg-yolk. That is pure unadulterated caustic soda.

Back in the day, easy off used to be sold in small wide-rimmed bottle with a little brush for application. That's what will get rid of your soapy fatty lime residue.

Solid granules or powder

If all you can get your hands on is the solid variety (dehydrated or deactivated lye) you will need to dissolve it in water. Make sure you add the lye to water, and not the other way around. Do this on a well ventilated area, as doing this will release caustic fumes and also heat (it's an exothermic reaction ) here is a video showing bhow to do it properly. Notice the consistency of the solution and the safety gear used. Also, this is done out in the open, since an extraction hood was not available to eliminate the fumes.


Safety first

Glass is impervious to Sodium Hidroxyde, however in the reaction with lime, after dissolving the encapsulated fat and soap will vaporize and create chemically reactive fumes which if accidentally inhaled will at best irritate and at worse cause chemical burns on any mucous membrane they come in contact with, (eyes, lips, sinuses) so it goes without saying, WEAR A MASK AND GOGGLES in addition to rubber gloves when handling caustic soda. A handkerchief and eyeglasses will do, but ventilate the area appropriately after application.

Also, water will make it "jump" (if you drop some on the toilet, for example)

As for the cleaning procedure, just apply a coat with a brush, let it sit for a few minutes then clean up with a wet disposable fabric towel. Then rinse thoroughly with running water. Do not use the shower head for that purpose since that will make any caustic soda film that you may have missed jump in tiny droplets, that will probably cause tiny skin burns or may dissolve and create tiny holes in your clothing.

Caustic soda is probably second only to nitric acid in chemical reactiveness and deserves to be treated with respect.

if all else fails

If that doesn't get rid of the residue, there is only one other solvent that may get rid of it, but I don't recommend it being handled by anyone without laboratory experience: Piranha Solution Wich is a reactive mix of Sulfuric acid with Hydrogen Peroxide. and is used to clean laboratory glassware from stubborn organic char residue.

Try your luck with Sodium Hydroxide first

  • Thanks for this suggestion - I never considered that Caustic Soda might be worth trying - and actually have some in the house already so it is easy for me to try. When I buy it here (UK) it normally seems to come as a granular powder, I assume I will have to mix with a small amount of water to form a thick paste...?
    – Lefty
    Commented Apr 24, 2017 at 20:32
  • @Lefty I'd follow the instructions on the packaging. In it's solid state what you've got is probably deactivated lye, which should have a soapy consistency to it. Adding the right amount of water is essential for it to "reactivate" into the base alkaline Sodium Hydroxide =)
    – hlecuanda
    Commented Apr 24, 2017 at 21:04
  • Excellent. Will have a look. I also had a look at the "Drain Unblocker" gel that I always keep in the house too. THAT contains Sodium Hydroxide but no suggestion as to what concentration. Maybe I'll try the gel first, since it's easiest.
    – Lefty
    Commented Apr 25, 2017 at 8:00
  • @Lefty I've amended my answer, adding a video on how to disolve your lye granules into a usable solution. Hope it helps.
    – hlecuanda
    Commented Apr 25, 2017 at 20:08
  • I've tried the "Drain Unblocker" to no avail. I left it it in contact with the glass for about 6 hours and nothing. Next try, caustic soda...
    – Lefty
    Commented Apr 30, 2017 at 16:20

From what I could see in a well focused portion of the image you had posted

enter image description here

there is a diffraction of light at the rims of the "stains". This would not be expected from ordinary limescale but indicates that the surface of your door was damaged.

This may come from an aged surface coating or from acrylic glass of your door. This may also be the result of treating the coating, or acrylic glass with a cleaner capable of partly dissolving it.

To avoid replacing the door we can hide the stains by applying a frosted or etched glass film. Transparency will be lost by this.

  • Nice idea, but I don't think so. The door is about 8 years old and the problem didn't really materialise until about the 3rd year. It has got worse continually since then. Both doors are cleaned the same way but this one is much worse than the other.
    – Lefty
    Commented Dec 20, 2015 at 15:07
  • 1
    To confirm that this is etching, you could take a straight-edge razor and scrap it. If it comes off, it's precipitate of some sort, if not, there won't be a simple way to fix it and @Takkat's idea stands as a good idea.
    – Minnow
    Commented Dec 20, 2015 at 17:12
  • 1
    @Minnow I've tried scraping it with a razor scraper and it does scrape off but is very, very, hard.
    – Lefty
    Commented Dec 20, 2015 at 18:09
  • @Lefty: it still could be some coating or a protective film that came off.
    – Takkat
    Commented Dec 20, 2015 at 19:39
  • @Takkat No, it's not. The build-up is most prevalent on the areas where water hits it most often. For instance, the top of the door is almost completely clear. I'm prepared to concede that it may be a result of soap/shampoo contacting the glass in those areas - but it's not a coating that came off.
    – Lefty
    Commented Dec 20, 2015 at 19:44

I use vinegar to remove such stains. Also, on glass you might try using a razor blade scraper. I have a mirror hanging in the shower, and once every few months I just use the razor blade to slice off the built up lime. I push the blade forward (it's in a holder) and peel off the build-up, and then wash it with vinegar.

  • Thanks for the suggestion. I have a razor scraper but it was very difficult to remove a very small amount when I tried it so am very keen to use a chemical means if I can. I will try vinegar with the paper-towel-assist discussed above but it has been no use on it's own in previous trials.
    – Lefty
    Commented Dec 24, 2015 at 22:44

I have THE answer. For many years, I had a business restoring and renovating bathrooms. In my trade, I used a number of professional products yet NONE have compared to this product for removing lime, rust, and other deposits that don't respond to the usual commercial or home remedies. Its only caveat is the surface must be semivitreous and it does work on glass. Best part: super cheap!

Easy to use, very little time or elbow grease involved. Wet the 'stick' and rub on stain vigorously. Rinse with clear water. Repeat if necessary.

I have used this product on myriad surfaces; stone, tile, grout, glass, ceramic sinks, tubs and toilets, chrome fixtures, faucetry, and all with a great result and little effort.

Lastly, once you've removed the stains, clean thoroughly and apply this treatment. It allows water to bead and surfaces to stay relatively stain free. After restoration, keep and use a squeegee in the shower to eliminate future staining. It literally takes about 10 seconds.

I do not work for any of the companies who's products I recommend.


This comes too late to help you, but hopefully this can help some other people.

If the glass is truly glass (and not acrylic), you can use steel wool to clean off the deposits. Steel wool does not scratch glass, and does a wonderful job at removing any type of deposits. There is also a product called FLITZ that is a paste that helps dissolve deposits. It's a bit easier to use on vertical surfaces than liquid cleaners like CLR, because it's stays put until you wipe it off.

  • It's not too late - I have yet to find any suitable way of removing this build-up, so it continues to worsen. I might try steel wool on an "inconspicuous area" - I already have some in the house but the thought of using it on glass gives me a problem...! I'd really like to understand what this build-up actually is and why it doesn't respond to normal scale chemicals that work perfectly well on thick deposits on taps etc. Especially since the water softener means the scale content is very low.
    – Lefty
    Commented Mar 15, 2017 at 8:22
  • @Lefty Even if you have soft water, you could still be getting scale deposits (especially if you shower with hot water). Hot water can hold more of a dissolved substance than cold water, so you'd get larger deposits than usual as soon as it touches the cold glass. I don't know why the cleaners designed for scale don't work, but I wouldn't rule it out just based on your water softener. Have you tried posting on chem.stackexchange.com? They may be able to give you some good suggestions on how to narrow down or identify the deposits.
    – Jacob
    Commented Mar 15, 2017 at 13:36
  • @Lefty And as for steel wool, if it helps to allay your concerns, it's used by detail shops everywhere to clean automotive glass.
    – Jacob
    Commented Mar 15, 2017 at 13:39
  • @Lefty I've amended my answer, adding a video on how to disolve your lye granules into a usable solution. Hope it helps.
    – hlecuanda
    Commented Apr 25, 2017 at 20:07
  • I have now tried steel wool - see my update to the question.
    – Lefty
    Commented May 13, 2019 at 7:40

So, to me, the pattern of your water spots look so regular as to be a design...but you say it varies and gets worse so here’s what works miracles por moi: COPPER CLEANER left to soak for twenty then scrubbed off with dampened black and white NEWSPAPER. Then glass cleaner tot remove the residual gunk....if that doesn’t work, maybe make an algorithm that calculates cost/benefit ratio versus just throwing in the proverbial towel and, thus, buying a new door. Maybe add up how much money has been spent on random cleaning products, how many hours spent scraping/scrubbing/scouring, depth of unnecessary wrinkles cut into your face from grimacing at the door every day whilst shampooing, eons spent asking for and taking advice from complete strangers(and potential whack jobs...) on stackexchange.com, ad infinitum....and compare that to remodeling your whole bathroom. You’ll probably have enough left over to do the kitchen, too!


Use medium-fine grade steel wool and a spray cleaner like formula 409, rinse often.

  • Surely steel wool will scratch the glass.
    – Chenmunka
    Commented Jan 1, 2019 at 18:34
  • no it will not, shower door glass is specially hardened and cannot be scratched by medium-fine steel wool. Commented Jan 1, 2019 at 19:21
  • @nielsnielsen Thank you - see my update to the question.
    – Lefty
    Commented May 13, 2019 at 7:40
  • if hydrochloric did not remove it, then it is not lime buildup but chemical weathering of the glass surface. I would consult a glass shop for their advice. Commented May 13, 2019 at 15:09

I restore antique stoves. They are vitreous enamel...like glass

We use steel balls (not wool. The scrubbing balls with thicker strands of looser metal) from most supermarkets. It will not scratch glass. Wire wool will. So will green pads.

Mix a cup of bicarbonate of soda with half a cup of ecover or other veg based washing up liquid (I don't know why it's better but it is. I also use liquid savon de marseille because I'm in France)

Slowly add a cup of white vinegar, mix all the time. It will froth a LOT. Use a BIG BOWL.

Paint it on. Leave 24-48 hrs to dry. Scrub off with steel ball and hot water Rinse with cold.

This works on engine grease rust paint and 150 year old baked on soot. It should work on limescale and soap grease.


Drill Brush works great for me. After years of strenuous hand scrubbing and trying every recommended cleaning solution under the sun and at best getting barely acceptable results, I saw the drill brush and decided to give it a try. My shower has never been so clean. It still took a while to get the lime stains off the glass but it wasn't strenuous at all. Make sure you get the big ball brush and the flat one. The ball brush cleans everything but the stubborn stuff. The flat brush cleans the hard to get off things, like the lime from the glass.


Have you tried looking at a product called "Glass Rescue"? I saw it in a youtube video and they say it works for hard stuck-on glass stains. Maybe you can give that a try if abrasives and other solutions don't work!

I personally haven't tried it, as my bathrooms don't have glass doors.

  • Can you provide a link to video or product. See How to Answer.
    – Minnow
    Commented Dec 24, 2015 at 22:44
  • @Newbie I tried to find it on Youtube but couldn't. If it only works for "stains" then I doubt it will dissolve the limescale...?
    – Lefty
    Commented Dec 24, 2015 at 22:47

Your solution is HNO3 (Nitric acid) + water.You may search markets for selling a solution with HNO3.It helped me.

You may find details about by the link below :

HNO3-Nitric Acid


I had a home staging biz when the market was hopping and although this won't remove the hard calcium build-up, I do have a couple valueable tips.

  1. As a preventative measure to build-up, apply car wax and polish it in just like you do on your vehicles. It works beautifully! The water will bead right up and a sgueegee will do the rest. Reapply as often as needed to maintain the protective coating.

  2. For aesthetic purposes only: If you get tired of looking at that white, chalky, gunk or if you have company coming over and want it to look nice, clean your shower door as good as you can then dry it. Next, rub on some lemon, orange or coconut oil.

This will turn the white deposit clear and smells good, too. It's only temporary but will last a few days. It can be reapplied as often as you like.

Just make sure that the surface you stand on is free from the oil before you shower because it can be very slippery otherwise.

I hope these easy tips will at least reduce some frustration.

  • I like the idea about the car polish! Since I've given up trying to remove the scale, I assume that one day I will just get the glass replaced - and then I will make a point of keeping it polished in order to stop the problem from happening again.
    – Lefty
    Commented Apr 19, 2019 at 11:39
  1. Make sure that those "deposits" are not actually some degradation of the surface of the panel. I had the situation sometimes that the dirt was "growing" while cleaning - until I understood that I was removing the surface coating and exposing the base material.
  2. Did you try to mechanically remove a small bit of those "deposits"? Just to see if they are truly deposits.
  3. If the answer to 2. is "yes", you might be able to find some company to make an analysis of that substance, so you can find an "enemy" for it.

As for solution, you received quite a lot of advice. I want to make a small suggestion, based on the other answers.

  1. Use some (strong) acid - to fight against lime.
  2. Use (strong) soap to fight against grease.
  3. Repeat.


  1. The acid must be moist in order to work. If it just stays there as a solid, it might become a part of the problem itself.
  2. The acid if best applied as a spray - it reduces the need of elbow grease.
  3. The soap should be used as any soap - mixed with elbow grease.
  4. To reduce the need of elbow grease (almost completely) you might use a round brush attached to a drill machine / electric screw-driver.
  5. Wear protective gear. You do not want any of those substances, especially in your eyes. Neither in your nose, mouth, ears...
  6. As much as possible, do not use abrasive stuff - you will create microscopic hooks for problems and additional deposits.
  7. Be very patient.
  8. Be careful to not destroy things in the bathroom with those chemicals.
  9. You can add a fourth step: use some (strong) alcohols. It may have the same result as holy water, but who knows.

Last resort alternatives:

  1. Replace the panel entirely with a new one - it will damage your ego, as you will have to admit defeat.
  2. Clean the panel thoroughly, then apply some good paint - the panel will probably stop being transparent, but the deposits will no longer laugh at you as loudly.

I have some "very good quality water" in my apartment, so the toilet gets yellow tint on the back, where the water residue temporarily flows after flushing.

I occasionally spray standard bathroom cleaner / corrosive (I think I have Cif, but I am not sure). The more I spray, the whiter the surface becomes. As soon as I forget to spray, the yellow wins again.

You may want to take a sample of water to be analyzed. It might give you a clue about the source of the problem. A (cheap?) water filter might help against further degradation of surfaces, pipes etc.

After a good night's sleep I came up with another idea:

Try applying a thin film of lacquer. Do this only: - after you properly clean the surface; - after you test it on a small "hidden" surface.

Different lacquers might have different effects.

I just realized: you already tried a lot of things. The surface is probably cleaner that it should be :D

This idea - to apply rather than to remove - might be your solution. Especially after I looked again at the last picture.


@Lefty, I had a sliding glass shower door with the same water scaling issue and have looked for years for a solution. I just found one today that completely took it off and it looks brand new. I wish I would have taken pictures to show the before and after but I was just so excited to have finally found a solution.

I used WEIMAN Glass Cook Top Cleaner and Polish. I squirted it on the scrubbing side of a Scotch-Brite Stay Clean Scrubber. I used elbow grease to really scrub a 1.5 foot square area. Then used paper towel wipe most of it off and another clean paper towel to buff it completely off. The scaling was gone and clean glass looked like new. I continued the same procedure to do the entire door. Took about an hour to do both doors but now they look like they did when they were installed. Hope it works for you.

  • 1
    My guess is that your WEIMAN product is similar to the "Hob-Brite" product that I mention in response to one of the other answers. I originally bought it to clean my ceramic hob and it is a bit of a cocktail of cleaning agents but with a fine abrasive added. When used (WITH steel wool) it had some effect, but not enough to really be practical, unfortunately!
    – Lefty
    Commented Jan 2, 2020 at 11:15

Not the answer you're looking for? Browse other questions tagged or ask your own question.