Grout is cement, and cement is porous. What turns a white floor grey is not one stain but a layer of soil and body oils that has soaked into the joint, which is also why mopping makes it look worse and why the fix has to involve a brush rather than more water.
The two-step method that works on cement grout
Clean grout in two passes: an alkaline cleaner to lift grease and general soil, then an acid-based cleaner to dissolve the mineral staining and the grey film. Agitate with a stiff grout brush in both passes, and rinse between them, or the second pass neutralises the first.
Prices are Freshway catalogue prices as at 16 September 2026 and are subject to change. Confirm the current price, and whether GST applies, before quoting.
Start alkaline, then go acid
Alkaline cleaners remove grease, oils and general soil. Acid cleaners dissolve the mineral deposits, efflorescence and the stubborn grey that remains after the first pass. Doing them in the wrong order — or mixing them together — wastes both products and can damage the grout.
| Product | Pass | Price |
|---|---|---|
| Research Products Punch | Alkaline: grease, oils and general soil | A$68.00 |
| Britex Grout & Tile Cleaner | Acid: mineral film and grout restoration, 1 L | A$20.00 |
| Actichem Tile & Grout Restore | Acid restoration compound for heavy build-up | A$110.00 |
Dilute to the label, not to instinct. Over-strength acid etches the grout surface and makes it hold dirt faster next time, which is how a floor ends up needing monthly restoration instead of a quarterly clean.
The brush matters more than the bottle
A flat mop cannot clean a 3 mm joint; the bristles never reach the bottom. What works is a narrow-headed grout brush with stiff nylon bristles, worked along the joint rather than across it.
| Item | Use | Price |
|---|---|---|
| Sabco tile and grout brush | Stiff hand brush for wall and floor joints | A$12.50 |
| Edco handy grout brush | Narrow brush for detail work around fittings | A$6.30 |
| Britex grout brush refill | Replacement head for the DIY grout system | A$10.00 |
Shower grout: a different problem
In a shower, the grey is usually soap scum and hard-water scale sitting on top of the grout, plus mould in the joint where water stands. Treat it in this order: remove the soap scum with an alkaline cleaner, descale with the acid pass, then kill any mould with a mouldicide rather than more bleach. Bleach whitens the surface and leaves the mould root, so the black return is a matter of weeks.
Where the grout is physically missing or crumbling, no cleaner will help. Re-grouting is a separate job, and the tiles need to be dry for several days before it can be done.
What not to clean grout with
- Bleach on its own. Kills surface mould, does nothing for grease or scale, and degrades some grout additives over time.
- Baking soda and vinegar together. They neutralise each other on contact. Either is useful alone; the mixture is theatre.
- Steam on old grout. Steam lifts soil well, but on a floor where the grout is already soft it blows the joints out.
- Acid on marble, travertine or limestone. Acid etches calcium-based stone. On those surfaces use a pH-neutral or alkaline cleaner and a grout brush only.
Keeping grout clean after the effort
Once the joints are white again, the routine that keeps them that way is boring and cheap: daily dust-mopping or vacuuming so soil does not reach the joint, a neutral pH cleaner for routine mopping instead of the alkaline product, and the acid pass only when scale appears. A floor sealing programme is the next step for porous grout in high-traffic areas; our carpet and floor care and floor and surface ranges cover the chemistry either side of the seal.
Questions we get asked most
- What is the best thing to clean your grout with?
- An alkaline cleaner for the grease pass, an acid-based grout cleaner for the mineral film, and a stiff narrow grout brush. Products are secondary to the brush reaching the bottom of the joint.
- How do I get my grout white again?
- Two passes with rinsing in between: alkaline first, then acid. If the joint stays grey after both, the grout has stained through rather than on the surface, and the realistic options are grout colouring or re-grouting.
- What is the best way to clean grout from tiles?
- Work in sections of about a square metre, apply the cleaner to the joint rather than the tile face, agitate along the line, and rinse before the product dries. Letting acid dry on grout is how it gets damaged.
- What should you not clean grout with?
- Avoid acid on marble and other calcium-based stone, avoid bleach as a general grout cleaner, and avoid mixing alkaline and acid products together. All three cause damage that shows up months later.
- Can I use a steam cleaner on grout?
- On sound, well-bonded grout, yes — and our steam cleaner range covers that method. On older or crumbling joints, steam lifts the grout and creates a bigger repair.
References
- SafeWork NSW — chemicals and other substances.
- NSW Environment Protection Authority — chemical handling and disposal.
Floor too big to hand-brush?
For anything larger than a bathroom, tell us the area and the grout age and we will recommend a machine or a restoration product instead of a brush and a weekend. Browse cleaning chemicals or ask our team.