How to Clean Grout Between Tiles Effectively

White grout goes grey. Grey grout goes black. It happens so gradually you don’t notice — until you see a photo of your bathroom from five years ago and realise it used to look completely different. So how do I clean grout between tiles effectively? The internet is full of “miracle” methods involving everything from toothpaste to oven cleaner. Most are either ineffective or damage the grout. Here’s what actually works, from gentle maintenance to full restoration.

Start with the least aggressive method

Golden rule of grout cleaning: start gentle and escalate only if needed. Grout is porous cement — harsh chemicals and abrasive scrubbing erode it over time, making it more porous and quicker to stain next time. Work through these in order.

How do I clean grout between tiles effectively? The methods

Level 1: Hot water + stiff brush (maintenance)

For grout that’s just dull: scrub with hot water and a stiff grout brush (£5–£8 — the narrow ones that fit between tiles). Use a proper grout brush, not a toothbrush (too soft, too small — you’ll be there all day). Work in small sections, rinse frequently. This handles surface dirt and is all you need for monthly maintenance.

Level 2: Bicarbonate of soda paste (the workhorse)

Mix bicarbonate of soda with water into a thick paste. Apply to the grout lines, leave for 10–15 minutes, then scrub with the grout brush and rinse. The mild abrasion lifts grime without damaging the grout. For extra power, spray with white vinegar after the bicarb has sat (the fizzing helps lift dirt from the pores) — then scrub and rinse thoroughly.

Important: Don’t use vinegar on natural stone tiles (marble, travertine, limestone) — the acid etches the stone. Bicarb paste alone is safe; vinegar is not.

Level 3: Steam cleaner (the heavy hitter for floors)

A steam cleaner with a grout nozzle (£60–£120 to buy, £25–£35/day to hire) blasts dirt out of grout pores with superheated steam — no chemicals at all. It’s dramatically effective on floor grout, which takes the most abuse. Work slowly, one metre at a time, and wipe up the dirty water as you go (otherwise it just resettles). For a whole bathroom floor, hiring one for a day is the best £30 you’ll spend.

Level 4: Dedicated grout cleaner (for stubborn staining)

When DIY methods plateau, use a proper grout cleaner — HG Grout Cleaner, Lithofin, or similar (£8–£15). These are formulated with the right pH and surfactants for cement grout (Which? reviews cleaning products if you want independent test results). Apply, dwell per instructions (usually 5–10 minutes), agitate with the brush, rinse thoroughly. Wear gloves and ventilate — they’re stronger than kitchen cleaners for a reason.

Level 5: What about bleach?

Bleach whitens grout dramatically — and it’s tempting. But: bleach doesn’t clean, it just bleaches. The dirt is still in the pores; you’ve just made it white. Worse, regular bleach use breaks down grout over time and can yellow it. Occasional use on white grout for mould spots is fine; as a routine cleaner, no. And never mix bleach with vinegar or other acids — chlorine gas is genuinely dangerous.

Room-specific advice

Bathroom grout (mould and soap scum)

Black spots on shower grout are mould, not dirt — they need a mould-killing approach. Spray with a dedicated mould remover (Dettol Mould & Mildew, HG), leave for 30 minutes, scrub, rinse. For persistent mould in the grout (not just on it), the grout may be too far gone — see “re-grouting” below. Prevention matters more than cure: run the extractor fan for 20+ minutes after showering, squeegee tiles, and fix any ventilation issues causing the damp.

Kitchen grout (grease)

Splashback grout collects airborne grease that water alone won’t shift. Use a degreaser (sugar soap solution or a kitchen degreaser spray), leave to dwell, then scrub. The bicarb paste method works well here too — bicarb cuts grease effectively.

Floor grout (ground-in dirt)

Floor grout is the toughest — it gets ground-in dirt, mop residue and wear. Steam cleaning is the answer for periodic deep cleans. For maintenance, mop with clean water (change it frequently — mopping with dirty water just deposits grime into the grout) and avoid “mop and shine” products that leave residue.

After cleaning: seal it (the step everyone skips)

Here’s what separates grout that stays clean from grout that’s filthy again in three months: grout sealer. Once the grout is clean and completely dry (wait 24–48 hours), apply a penetrating grout sealer (£10–£20 per bottle, covers a bathroom). It soaks into the pores and repels water, grease and stains. Apply with a small brush or applicator bottle, wipe excess off tiles immediately, and let it cure per instructions. Reapply every 1–2 years in wet areas. This single step probably doubles the time your grout stays clean.

When cleaning isn’t enough: re-grouting and grout pens

• Grout pens/whiteners (£5–£10): Essentially paint for grout. They look great for about 6–12 months, then wear — especially on floors. Fine as a cosmetic touch-up before selling; not a long-term solution.
• Re-grouting (£200–£500 professionally for a bathroom): If the grout is crumbling, cracked, or permanently stained deep in the pores, rake out the old grout (a grout rake, £8, or an oscillating multi-tool) and apply fresh grout. It’s labour-intensive but transforms the room — often making old tiles look new. Consider epoxy grout for showers: it’s waterproof, stain-proof and never needs sealing (but it’s harder to apply — usually a pro job).
• Darker grout: When re-grouting, consider mid-grey instead of white. It hides everything, looks modern, and you’ll never scrub it again with the same desperation.

The practical takeaway

Work the ladder: hot water and a grout brush for maintenance, bicarb paste for grime, steam cleaner for floors, dedicated grout cleaner for stubborn stains — and always seal afterwards. Ventilate bathrooms properly to prevent mould returning, and when the grout is truly past saving, re-grout (in mid-grey this time). Clean grout makes the whole room look renovated; it’s the highest-impact hour you’ll spend on your bathroom or kitchen this year. If the bathroom needs more than grout work, see how much a bathroom refit costs before you commit to tiles and sanitaryware.