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Why won't soap scum come off my shower glass?Updated 7 days ago

TL;DR: If your shower glass still looks cloudy after cleaning, it might not be soap scum at all. Mineral buildup or glass etching can look very similar but they behave differently. Soap scum responds to Bathroom & Shower Cleaner, dwell time, and light agitation. Mineral buildup needs more work or a specialist descaler. Etching is permanent surface damage that no cleaner will fix. Use the checks below to figure out what you're dealing with.


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Koh Bathroom and Shower Cleaner before and after
Koh Bathroom and Shower Cleaner problem and solution

What's actually on my shower glass?

Three things look similar on shower glass but are different problems. Soap scum is a film of soap, body oils, and grime sitting on top of the glass. It's removable with the right cleaner and patience. Mineral buildup is calcium and magnesium from hard water dried onto the glass. It feels hard or gritty under your fingertips. Glass etching is permanent microscopic damage to the glass itself, usually caused by long-term mineral exposure or acidic cleaners. It feels smooth but looks hazy, and no cleaner will fix it.

✓ Soap scum

Film from soap and body oils. Feels slightly slick or waxy. Responds to the right cleaner, dwell time, and gentle agitation.

Feels slick Removable

⚠ Mineral buildup

Calcium and magnesium from hard water. Feels hard or gritty. Needs repeat cleans or a specialist descaler to shift.

Feels gritty Removable with work

⚠ Glass etching

Permanent damage to the glass surface. Feels smooth but looks hazy. No cleaner will fix it, the glass needs replacing or resurfacing.

Feels smooth Not removable

How do I tell which one it is?

Run your fingertips across the cloudy area when the glass is dry. Slick or waxy texture suggests soap scum. Hard or gritty texture suggests mineral buildup. Smooth but still hazy suggests etching. Second check: clean a small patch thoroughly with Bathroom & Shower Cleaner, rinse and dry, then compare to the surrounding area in good daylight. If the cleaned patch looks noticeably clearer, it's soap scum or mineral buildup. If it looks identical to the cloudy surrounds, it's etching.

✓ Two quick checks

1

Fingertip test. Dry glass, run your fingertips across. Slick = soap scum. Gritty = mineral buildup. Smooth but hazy = etching.

2

Clean-patch test. Thoroughly clean a small area with Bathroom & Shower Cleaner. Compare to surrounds in good daylight. No visible improvement means etching.


How do I fix soap scum?

Spray Bathroom & Shower Cleaner, let the foam sit for 5 to 10 minutes (longer than the usual 2 to 3), wipe with Ultra Pro Bathroom Mitt, rinse thoroughly with water, and dry with a clean cloth. Repeat if needed, heavy soap scum can take two or three applications to fully shift. For really stubborn spots, step up to Diamond Sponge with light pressure (glass is tough but a Diamond Sponge still requires care).

✓ Soap scum fix

1

Spray and extend the dwell. 5 to 10 minutes, longer than the usual 2 to 3. Give the formula time to break the film.

2

Agitate with Ultra Pro Bathroom Mitt. Firm circular motion. Step up to Diamond Sponge for stubborn spots, light pressure only.

3

Rinse and dry fully. Water rinse, dry with a clean microfibre. Dry glass is clear glass. Repeat the cycle if needed.


What about mineral buildup?

Mineral buildup (calcium, magnesium, limescale) is calcium-based. Bathroom & Shower Cleaner is alkaline and doesn't dissolve mineral buildup effectively because minerals need an acidic cleaner to break down. For hard-water deposits, use a dedicated descaler like a vinegar-based product or commercial limescale remover. Apply sparingly, rinse thoroughly, and never combine with Bathroom & Shower Cleaner (mixing cleaners can deactivate both). Once the mineral layer is gone, switch back to regular cleaning to prevent recurrence.

⚠ Different chemistry needed

Mineral buildup is calcium-based. Bathroom & Shower Cleaner is alkaline and doesn't dissolve it effectively, minerals need an acidic descaler. Use a vinegar-based descaler or commercial limescale remover sparingly, rinse thoroughly, never combine with other cleaners. Once the mineral layer is gone, switch back to regular cleaning to prevent recurrence.

Acidic descaler Don't mix cleaners Rinse thoroughly

What if it's etching?

No cleaner will fix glass etching because the damage is to the glass surface itself, not a layer on top. Options are limited: professional glass polishing (an acid-based restoration service, sometimes effective on light etching), replacing the glass panel, or applying a protective coating like EnduroShield to new glass to prevent future etching. Prevention for future glass: squeegee after every shower with Bathroom Squeegee, dry seals and ledges, never let hard water dry on glass.

⚠ Etching isn't cleanable

The damage is to the glass, not a layer on top. Options: professional glass polishing (sometimes effective on light etching), or replace the panel. Prevention for future glass: squeegee after every shower with Bathroom Squeegee, dry seals and ledges, never let hard water dry on glass.

Professional polish Replace panel Squeegee daily

Still not happy with the result?

If you've worked through the checks and Bathroom & Shower Cleaner isn't delivering what you expected, reach out to our team. Send a photo of the glass and a quick description of what you've already tried. We'll help troubleshoot the specific situation and, if needed, back it with our 30-day money-back guarantee.

✓ 30-day money-back guarantee

Worked through the checks and Bathroom & Shower Cleaner still isn't delivering? We'll help troubleshoot, and back it with our 30-day money-back guarantee if needed.

30-day guarantee

Koh Bathroom and Shower Cleaner 1.8L

Bathroom & Shower Cleaner · for soap scum and bathroom build-up

Sensitive Choice approved, Dermatest tested, Eczema Association recognised. 12 ingredients, pH 8, made in Australia.

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Bathroom & Shower Starter Kit pairs the formula with Foaming Spray Bottle, Ultra Pro Bathroom Mitt, and Bathroom Squeegee.

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Last reviewed: April 2026


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