Dirty, darkened grout can make even a freshly mopped floor look grubby. The tiles shine, but those grey or yellow lines between them drag the whole room down. The good news: in most cases you don’t need to replace anything — with the right method you can clean grout and bring it back to white, using things you probably already have at home.
This guide walks you through every method, from a simple everyday clean to bringing badly stained, yellowed grout back to white. We’ll go from the gentlest approach to the strongest, explain what to use where, and — importantly — warn you about the methods that can quietly damage your grout or tiles if you’re not careful. Whether it’s a bathroom wall, a kitchen floor, or old discoloured lines you’d given up on, there’s a fix here.
Quick answer
For a fast result: make a paste of baking soda and water, spread it on the grout, spray or drizzle a little vinegar over it, let it fizz for a few minutes, then scrub with a stiff brush and rinse. For tougher, yellowed grout, use a dedicated grout cleaner or an oxygen-bleach paste, and for grout that won’t come clean at all, a grout pen or resealing will restore the white. We’ll cover each in detail below.
Why does grout get dirty and turn yellow?
Understanding why grout discolours helps you clean it properly and keep it clean. Grout is slightly porous, so it soaks up whatever lands on it:
- Dirt and foot traffic grind grey grime into floor grout over time.
- Soap scum and hard-water minerals build up on bathroom grout, leaving a dull, yellowish film.
- Mould and mildew thrive in damp bathroom joints, showing as black or pink spots.
- Grease and cooking residue darken kitchen grout.
- Cheap or unsealed grout stains far faster because it absorbs everything.
Because the staining soaks into the grout rather than sitting on top, a normal mop won’t shift it — you need to lift it out, which is what the methods below do.
Before you start: a few safety notes
A quick, honest word before you grab the cleaning supplies, because some popular “hacks” can damage your floor:
- Vinegar is acidic. It works on regular cement grout and hard-water film, but it can etch and damage natural stone tiles (marble, granite, limestone) and, over time, weaken some grout. If your tiles are natural stone, skip vinegar and use a pH-neutral or stone-safe cleaner.
- Never mix bleach with vinegar or with any ammonia-based cleaner. The combination releases toxic fumes. Use one product at a time, and rinse between them.
- Ventilate the room when using bleach or strong cleaners, and wear gloves.
- Test any method on a small, hidden patch first, especially on coloured grout or natural stone.
With that said, here are the methods, from gentlest to strongest.
Method 1: Everyday clean with warm water and a brush
Start simple. For lightly dirty grout, warm water and a stiff brush do more than people expect.
- Dip a stiff-bristled brush in warm water.
- Scrub along the grout lines firmly.
- Wipe away the loosened dirt with a cloth.
- Rinse and let dry.
This won’t fix deep stains, but it’s the right first step and often enough for regularly cleaned grout. An old toothbrush works for small areas; a dedicated grout brush is far faster for floors.
Method 2: Baking soda and vinegar (the classic home method)
This is the most popular home method for a reason — it’s cheap, effective, and works on most cement grout.
- Mix baking soda with a little water into a thick paste.
- Spread the paste over the grout lines.
- Fill a spray bottle with a 50/50 mix of white vinegar and water and spray over the paste — it will fizz.
- Let it sit for 5–10 minutes.
- Scrub with a stiff brush along the lines.
- Rinse thoroughly with clean water and wipe dry.
The fizzing reaction lifts dirt out of the porous grout. Remember the caution above: don’t use vinegar on natural stone. For stone, use baking soda with water only, or a stone-safe cleaner.
Method 3: Baking soda and hydrogen peroxide (for whiter results)
If plain baking soda and vinegar isn’t getting it white enough, swap the vinegar for hydrogen peroxide, which has a mild whitening effect and is gentler on grout than vinegar.
- Make a paste of baking soda and hydrogen peroxide (3% household strength).
- Apply it thickly to the grout.
- Leave for 10–15 minutes.
- Scrub and rinse.
This combination both cleans and lightens, making it a good step up for yellowed grout without the acidity of vinegar.
Method 4: Oxygen bleach (best for badly stained grout)
For grout that’s really stained or greyed, oxygen bleach (a powder that you mix with water — different from harsh chlorine bleach) is one of the most effective and safest options. It’s colour-safe and won’t give off strong fumes.
- Mix the oxygen-bleach powder with warm water as directed.
- Apply generously to the grout and let it soak for 10–15 minutes (don’t let it dry out).
- Scrub with a stiff brush.
- Rinse well.
Oxygen bleach lifts deep stains without damaging grout or coloured tiles, which makes it a favourite for tough floor grout.
Method 5: A dedicated grout cleaner
When home methods aren’t enough, a ready-made grout cleaner is formulated for exactly this job and saves effort. Choose one suited to your tile type (stone-safe if you have natural stone).
- Spray or apply along the grout lines.
- Leave for the time stated on the label.
- Scrub with a stiff brush.
- Rinse thoroughly.
These are the fastest route for large or heavily soiled areas, and worth keeping on hand for bathroom grout.
Method 6: Chlorine bleach (last resort, white grout only)
For stubborn mould stains on white grout, diluted chlorine bleach works — but treat it as a last resort and use it carefully.
- Dilute bleach with water (a weak solution).
- Apply only to the stained grout, avoiding coloured grout and natural stone.
- Ventilate the room well and wear gloves.
- Leave briefly, scrub, and rinse thoroughly.
Never mix bleach with vinegar or ammonia. Bleach can weaken grout and discolour coloured grout over time, so don’t make it your regular method — it’s for occasional tough mould only.
How to make grout white again when cleaning isn’t enough
Sometimes grout is so old, worn, or permanently stained that no amount of scrubbing brings the white back. In that case, you restore the colour rather than clean it:
Use a grout pen
A grout pen is a quick, cheap fix that paints a fresh layer of white (or coloured) coating over clean, dry grout. It’s ideal for tidying up small areas or refreshing bathroom lines, and the result looks crisp and new. Clean and dry the grout first, run the pen along each line, and let it cure.
Re-grout as the ultimate reset
If grout is cracked, crumbling, or beyond saving, the permanent solution is to remove the old grout and apply new. It’s more work, but it gives a completely fresh finish. For a large area this is a job many people hand to a tiler.
Seal it to keep it white
Once your grout is clean and dry, applying a grout sealer is the single best thing you can do to keep it white. Sealer stops the porous grout from absorbing dirt and moisture, so it stays cleaner for far longer and resists staining. Reseal every year or so in wet areas.
How to keep grout white longer
Cleaning grout is satisfying, but keeping it clean is easier than repeating the job. A few habits go a long way:
- Wipe bathroom walls after showering to reduce soap scum and moisture that feed mould.
- Ventilate wet areas — an exhaust fan or open window cuts the damp that mould loves.
- Seal your grout after cleaning, and reseal periodically.
- Wipe spills quickly in the kitchen before they soak in.
- Do a light brush-clean regularly rather than waiting for heavy staining to build up.
Room-by-room notes
Bathroom grout faces constant moisture, soap scum, and mould, so ventilation and sealing matter most here. Oxygen bleach or a bathroom grout cleaner handles most bathroom staining; a grout pen refreshes tired white lines.
Kitchen grout collects grease and food splashes, especially near the counter and stove. A baking-soda paste or a degreasing grout cleaner works well; wipe spills before they set.
Floor grout in living areas mostly darkens from foot traffic and dirt. Oxygen bleach and a good stiff brush restore it; sealing afterwards keeps it cleaner between deep cleans.
Mistakes to avoid
- Using vinegar on natural stone or too often — it can etch stone and erode grout over time.
- Mixing cleaning products — never combine bleach with vinegar or ammonia.
- Scrubbing with metal brushes — they can scratch tiles and gouge grout; use a stiff nylon brush.
- Letting cleaner dry on the grout — most work by staying wet for a few minutes; keep them damp.
- Skipping the seal — cleaning without resealing means the grout stains again just as fast.
The bottom line
In most cases, you don’t need to replace grout to get it white again — you need the right method for how dirty it is. Start gentle with baking soda, step up to oxygen bleach or a dedicated cleaner for tough stains, and if the grout is simply too far gone, a grout pen or fresh grout restores the white completely. Then seal it, and a few simple habits will keep it looking clean for far longer.
Clean grout is the quickest way to make an entire tiled room look new again — and now you know exactly how to do it.
Planning a new tiling project instead of cleaning an old one? Work out exactly how many tiles and how much adhesive you’ll need with our free tile calculator and adhesive calculator. And if you’re choosing tiles, our guide to vitrified vs ceramic tiles explains which to pick for every room.
Frequently asked questions
How do I make grout white again naturally? Make a paste of baking soda and water, apply it to the grout, then spray with a 50/50 vinegar-water mix (skip vinegar on natural stone), let it fizz, scrub, and rinse. For extra whitening, use baking soda with hydrogen peroxide instead of vinegar.
What is the best thing to clean grout with? For most grout, oxygen bleach or a dedicated grout cleaner gives the best results without damaging tiles. Baking soda paste works well for regular cleaning, and a grout pen restores white when cleaning isn’t enough.
Can I use vinegar to clean grout? Yes on regular cement grout, but not on natural stone tiles like marble or granite, which vinegar can etch. Used too often, vinegar can also wear down grout, so don’t make it a daily habit.
Why does my grout keep getting dirty so fast? Unsealed grout is porous and absorbs dirt, soap, and moisture quickly. Sealing your grout after cleaning stops this and keeps it white for much longer.
How often should I seal grout? In wet areas like bathrooms, reseal roughly once a year. In drier areas, every couple of years is usually enough. Always reseal after a deep clean.
Is bleach safe for grout? Diluted chlorine bleach can remove tough mould from white grout, but use it sparingly and never mix it with vinegar or ammonia. It can weaken grout and discolour coloured grout over time, so it’s a last resort, not a regular cleaner.
