Grout starts white (or grey) and ends up… not. Years of soap, hard water, mildew and general life turn it yellow, brown or black. The best way to clean grout between tiles depends on how bad it is — from a quick refresh to a full restoration. Here’s the complete playbook, in order of escalation.

Level 1: Routine cleaning (maintenance)

For grout that’s just dull, not disgusting:

• Spray with a daily shower cleaner or diluted washing-up liquid.
• Scrub with a stiff brush (an old toothbrush for small areas, a grout brush — £5 — for larger ones).
• Rinse and dry.

Do this weekly in showers and it’ll never get bad. The people with pristine 10-year-old grout aren’t lucky — they’re consistent.

Level 2: Deep clean (stained but sound grout)

The bicarbonate paste method

1. Mix bicarbonate of soda with water into a thick paste.
2. Apply to grout lines and leave 15–20 minutes.
3. Scrub vigorously with a stiff brush.
4. Rinse thoroughly.

Effective on soap scum and light staining. Cheap, non-toxic, and surprisingly good.

The vinegar upgrade (for limescale)

In hard water areas, grout staining is often limescale. Spray white vinegar onto the grout, leave 15 minutes, scrub, rinse. The acid dissolves limescale that alkaline cleaners can’t touch. Don’t use vinegar on natural stone tiles (marble, limestone, travertine) — the acid etches the stone. Fine on ceramic and porcelain.

Commercial grout cleaners

HG Grout Cleaner, Lithofin and similar (£8–£12) outperform DIY methods on heavy staining. They’re formulated for the job — stronger acids/alkalis in controlled concentrations. Follow the instructions exactly, ventilate well, wear gloves. For really bad grout, they’re worth the money.

The steam cleaner

A handheld steam cleaner (£30–£60) with a grout nozzle blasts grime out of grout lines with zero chemicals. Deeply satisfying and very effective — the heat kills mould too. If you have lots of tiled areas, it’s a worthwhile investment beyond just grout.

Level 3: Restoration (blackened or mouldy grout)

Bleach (carefully)

For white grout blackened with mould: apply diluted bleach with a brush, leave 10–15 minutes, scrub, rinse thoroughly. It works — but bleach weakens grout over time and the fumes are harsh. Ventilate well, never mix with other cleaners, and don’t use on coloured grout (it’ll bleach the colour unevenly).

Grout colourant / restorer

Grout pens and colourant sealers (UniBond Grout Reviver, Rainbow Chalk Markers — £8–£12) paint over stained grout with a waterproof coating. They’re not a deep clean — they’re a cover-up — but on grout that’s structurally sound and just ugly, the result looks like regrouting for 5% of the effort. Lasts 1–2 years in showers. Choose the colour carefully; “white” pens on aged white grout can look patchy.

Hydrogen peroxide

For mould that resists everything else: 3% hydrogen peroxide (from the chemist, £2) applied to grout, left 10 minutes, scrubbed off. It’s a powerful oxidiser that kills mould at the root. More effective than bleach on porous grout, less damaging. Wear gloves.

Level 4: When cleaning isn’t enough — regrout

If the grout is crumbling, cracked, or stained so deeply that nothing shifts it, cleaning is wasted effort. Regrouting (£30 in materials, a weekend’s work) gives you literally new grout. And if the silicone around the bath or shower is the mouldy part, that’s a separate job — cut it out and replace it; no cleaner fixes perished silicone.

Keeping it clean: the prevention routine

• Squeegee after showering. The 30-second habit that prevents 80% of grout problems.
• Ventilate. Extractor fan during + 20 minutes after. See our guide to stopping bathroom mould — mouldy grout is usually a ventilation failure, not a cleaning failure.
• Seal the grout. A grout sealer (£10–£15) applied to clean, dry grout repels water and stains. Reapply annually in showers. It won’t make grout invincible, but it buys significant time.
• Weekly wipe-down. A quick spray and wipe with bathroom cleaner prevents buildup. The deep cleans become unnecessary.
• Fix leaks promptly. Constant moisture from a dripping tap or failed seal overwhelms any cleaning routine.

What NOT to do

• Don’t use wire brushes or abrasive pads on grout — they gouge it, creating more surface for dirt to grip.
• Don’t use coloured bleach or toilet cleaner on grout — the dyes stain, and the harsh chemicals degrade it.
• Don’t seal dirty grout — sealer over grime locks the grime in permanently. Clean first, seal second.
• Don’t ignore the cause. If grout keeps going mouldy within weeks of cleaning, the problem is moisture, not dirt. Fix ventilation first.

Grout haze: removing the cloudy film

After regrouting or deep cleaning, a cloudy grout haze sometimes remains on the tiles — a thin film of cement residue. It looks like the tiles are permanently dirty. The fix:

• For recent haze (within days): buff vigorously with a dry cloth or hessian. Often that’s enough.
• For stubborn haze: a specialist grout haze remover (£8–£12, e.g., Lithofin or HG) dissolves the residue without harming the grout. Apply, wait, scrub, rinse thoroughly.
• Never use on natural stone without checking compatibility — acid-based haze removers etch marble and limestone. Use a pH-neutral residue remover for stone.
• Prevention: the haze comes from overwashing during grouting (too much water on the sponge). Next time, wring the sponge harder and change the water often.

Grout cleaning tools worth buying

• Grout brush (£5): stiff V-shaped bristles that get into the joint. The single most useful grout tool.
• Electric grout cleaner (£25–£40): oscillating brushes that do the scrubbing for you. Worth it for large tiled areas or anyone with wrist problems.
• Steam cleaner (£40–£80): the deep-clean weapon — blasts grime out with zero chemicals. Also brilliant for ovens, hobs and upholstery.
• Old toothbrushes: free, and perfect for taps, corners and fiddly bits. Keep a jar of them under the sink.

For product-specific cleaning advice, HG’s cleaning guides cover grout, limescale and mould with tested methods for each surface type.

The takeaway

The best way to clean grout between tiles: weekly maintenance with a brush and bathroom cleaner; bicarb paste or vinegar for deep cleans; steam or commercial grout cleaner for heavy staining; grout pens for cosmetic refresh; regrouting when it’s beyond saving. And afterwards, squeegee and ventilate — because clean grout stays clean only if it stays dry.