Short answer: For routine cleaning, a mild washing-up liquid and a soft brush are enough. Against lime soap an acidic bathroom cleaner works, against grease an alkaline one. It is worth doing the scratch test first: if you can lift the discolouration off with a fingernail, it sits on the joint and will come off. If the colour tone stays unchanged, it sits in the material – then no cleaning helps, only replacement. Two warnings: never mix chlorine cleaners with products containing vinegar or citric acid, as this produces toxic chlorine gas. And no acid on natural stone – it destroys the stone next to the joint.
Why silicone joints get dirty in the first place
A silicone joint is not smooth, even if it looks that way. Its surface is slightly rough and becomes rougher over the years, because plasticisers and fillers slowly migrate to the surface and fine micro-cracks form.
Three things collect in these cracks, and they need different treatment:
- Soap and grease film from shower gel, shampoo and care products – the most common deposit, yellowish to grey
- Lime soap, the compound of lime in tap water and soap – whitish, stubborn, grows in layers
- Mould, which feeds on the organic components – black to reddish spots, often in clusters
What you are dealing with determines the product. Anyone who tackles grease with an acidic bathroom cleaner is right to be surprised by the result.
The scratch test: is cleaning worthwhile at all?
Before you buy any product, do this test. It takes ten seconds and decides the whole afternoon.
Run your fingernail or a plastic card firmly over the discoloured spot. If a film lifts off or the strip underneath is clearly lighter, the dirt sits on the surface – cleaning is worthwhile. If the colour tone stays unchanged, the silicone itself is discoloured or grown through all the way. Then no cleaner will achieve anything, whatever it says on the bottle.
The same applies to mould: if it sits on top as a coating, it comes off. If the mycelium has worked its way into the material – recognisable by the black spots returning within days after cleaning – the joint has reached the end of its life. More on this in our guide Preventing and removing mould in silicone joints.
Routine cleaning
Regular care needs no special products.
Warm water with a little washing-up liquid, a soft brush or an old toothbrush, leave to act briefly, scrub along the length of the joint, rinse thoroughly and – the most important step – wipe dry. Standing moisture is the basis for everything that follows.
For heavier soiling, the deposit determines the product:
| Deposit | Recognisable by | Suitable product |
|---|---|---|
| Lime soap, water stains | whitish, matt, rough layer | acidic bathroom cleaner, citric acid |
| Soap and grease film | yellowish-grey, greasy | alkaline cleaner, washing-up liquid, all-purpose cleaner |
| Surface mould | black to reddish spots | chlorine-based anti-mould spray |
| Dust in micro-cracks | evenly grey joint | brush, washing-up liquid, mechanical |
| Discolouration in the material | scratch test shows no change | none – replace the joint |
Household remedies: a reality check
Vinegar and vinegar essence – with reservations
Works well against lime and lime soap and inhibits mould on the surface. But: acetic acid attacks the silicone with frequent use and makes the surface rougher over time – so new dirt settles faster. Heavily diluted and used occasionally, vinegar is fine; as a permanent solution it is not. Never on natural stone: acid dissolves marble and limestone and leaves dull etching marks that never go away.
Bicarbonate of soda and baking powder – mechanical, not chemical
Mixed with water into a paste and applied with a toothbrush, it is mainly the fine grain that does the work – it is a mild scouring agent. That helps against deposits on the surface, but not against discolouration in the material. Because it is mildly abrasive, use it sparingly and not regularly.
Citric acid – like vinegar, but with less odour
Works against lime and smells nicer. The same restrictions as with vinegar: not on natural stone, not permanently, rinse well. Do not use it warm – this can form poorly soluble calcium citrate, which makes matters worse.
Chlorine cleaners – effective, but with rules
Chlorine-containing anti-mould sprays are the most effective product against surface mould. They bleach the pigment and kill the growth on the surface. But note: ventilate well, wear gloves, wear eye protection when spraying, observe the contact time, rinse thoroughly. And the hard rule: never combine with acidic products, not even one after the other without thorough rinsing in between.
Important safety note: Chlorine-containing cleaners and acidic products such as vinegar, vinegar essence, citric acid or acidic bathroom cleaner must neither be mixed nor used directly one after the other. This produces chlorine gas, which damages the airways even at low concentration. If you want to use both products, rinse thoroughly with clean water in between and ventilate the room.
What you should avoid
Scouring agents and steel wool. They scratch the silicone surface permanently. Dirt settles even faster in the scratches than before – after a few weeks the joint looks worse than before cleaning.
The steam cleaner. Popular, but risky in sanitary areas: the combination of heat and mechanical pressure can detach the joint from its flanks. Once it is loose, water runs behind it.
Utility knives and metal scrapers. Completely unsuitable for cleaning. They cut into the joint and, in waterproofed bathrooms, damage the waterproofing underneath – damage that nobody notices.
Contact times that are too long. Leaving an aggressive product to act overnight helps no more than the intended time, but attacks the silicone and the grout.
Deep clean step by step
If the joint has not been treated for a long time, this procedure helps. It takes about half an hour per bathroom.
1. Pre-clean and dry
Remove loose dirt and the soap film with warm washing-up water, rinse thoroughly and dry the joint. On a wet joint every product is diluted and works less well.
2. Choose a product and test it on one spot
First identify the deposit, then choose the matching product. Always test first on an inconspicuous spot – especially with coloured joints, acrylic baths and anything that is not a glazed ceramic substrate.
3. Leave to act – for the stated time
Apply the product and observe the contact time stated on the bottle, not longer. On vertical joints, a strip of kitchen paper laid on top keeps the product in place instead of letting it run off.
4. Brush along the length
Soft brush or old toothbrush, working with moderate pressure along the joint. Scrubbing across presses dirt into the micro-cracks and works against the joint edge.
5. Rinse thoroughly and dry
Residues of any cleaner must go – otherwise they keep attacking and attract new dirt. Finally wipe dry and ventilate the room.
Special cases
Natural stone next to the joint
Marble, limestone, travertine and light granite react sensitively to acid. Vinegar, citric acid and acidic bathroom cleaners etch the surface matt, and this is not reversible. Use only pH-neutral cleaners or those expressly suitable for natural stone – and mask off generously.
Acrylic and sanitary acrylic baths
Acrylic is soft and sensitive to scratching. No scouring agents, no hard brushes, no solvent-based cleaners – the latter can cause fine stress cracks. Mild washing-up liquid and a soft sponge are the safe choice here.
Coloured and dark silicone joints
Chlorine-containing products bleach not only the dirt but also the pigment. On grey, anthracite or brown joints this leaves light patches that stay. Only chlorine-free cleaners belong here.
Kitchen instead of bathroom
At the worktop and sink, grease dominates, not lime soap. There an alkaline degreaser works considerably better than an acidic bathroom cleaner. For joints near food, rinse particularly thoroughly afterwards.
Silicone joint or grout – not the same thing
In the bathroom, two kinds of joint lie directly next to each other, and they tolerate different treatment. The grout between the tiles is cement-bound, mineral and absorbent – it tolerates more vigorous brushing, but reacts sensitively to acid, which dissolves the cement. The silicone joint in the corners and at the edge of the bath is elastic, non-absorbent and sensitive to mechanical abrasion.
Anyone who treats both with the same acidic product and a hard brush will generally damage both: the grout is washed out and turns sandy, the silicone is roughened. Treat the areas separately for that reason – first the tile joints, then the silicone joints, each with the suitable product.
When cleaning no longer makes sense
There is a point at which any further cleaning only costs time. Replace the joint if any of these signs applies:
- The scratch test shows no change – the discolouration sits in the material
- Black spots return within days after cleaning
- The joint has cracks or is coming away on a flank
- It can be lifted with a fingernail
- There is a musty smell behind the joint
A sanitary joint is a maintenance joint with a limited service life – depending on use and ventilation, five to ten years is normal. Replacing it is not the repair of a defect but planned maintenance. How to do it properly is explained in our guide Replacing sanitary silicone step by step.
Prevention is easier than cleaning
Squeegee briefly after showering. The single most effective step of all. Where no water stands, neither lime soap nor mould forms. A squeegee on the shower wall costs little and saves half the cleaning work.
Ventilate instead of just heating. After showering, open the window or leave the ventilation running until the moisture is gone. A bathroom without a window needs a working extractor – if it cannot hold a sheet of paper, it is too weak or blocked.
Less care product on the joint. Shower gels and hair conditioners leave exactly the film that mould feeds on. Rinsing the joint with clean water now and then is already enough.
The right silicone from the start. Sanitary silicones have a fungicidal finish and resist mould growth considerably longer than a simple building silicone. At the next replacement, it is worth reaching for the right product group.
Frequently asked questions
How do I best clean silicone joints?
For routine, warm water with washing-up liquid and a soft brush, then wipe dry. Against lime soap an acidic bathroom cleaner helps, against grease an alkaline one, against surface mould a chlorine-containing anti-mould spray.
Can you clean silicone joints with vinegar?
Occasionally and heavily diluted, yes; vinegar works well against lime. With frequent use the acid attacks the silicone and makes the surface rougher. On natural stone, vinegar is strictly taboo.
What helps against yellowed silicone joints?
First do the scratch test. If the yellowish film sits on top, an alkaline cleaner or a bicarbonate paste helps. If the silicone is discoloured all the way through, no cleaning helps any more – the causes and how to tell them apart are described in our guide Silicone joint turning yellow.
How do I get dust out of silicone joints?
Dust settles in micro-cracks and can almost only be removed mechanically: soft brush, warm washing-up water, scrub along the length. If the joint stays evenly grey afterwards, the surface has aged – then only replacement helps.
Can you use chlorine cleaner on silicone?
Yes, against surface mould it is the most effective product. With good ventilation, with gloves, observing the contact time and with thorough rinsing. Never together with acidic products – this produces chlorine gas.
Does a steam cleaner help with silicone joints?
It loosens deposits well, but heat and pressure can detach the joint from its flanks. In sanitary areas it is therefore not recommended – especially not on older joints.
Which brush is suitable for silicone joints?
A soft nylon brush or an old toothbrush. Brass brushes, scouring pads with abrasive fleece and steel wool are unsuitable – they scratch the surface permanently, and dirt then settles in the scratches faster than before.
Can you bleach silicone joints?
Chlorine-containing products bleach the pigment of the dirt and make white joints look lighter again. What they cannot do: lighten silicone that is discoloured all the way through. And on coloured joints they bleach the pigment as well – leaving light patches that stay.
Do shaving foam or toothpaste help against discoloured joints?
Both are household-remedy classics from the internet, and both work mainly mechanically through fine abrasive particles. Against light surface deposits that can be enough, against lime soap or mould it cannot. Drawback: the abrasive effect is hard to dose and roughens the joint.
What should I do if the mould comes back after cleaning?
Then the mycelium sits in the material, not on it. Further cleaning achieves nothing. The joint has to be replaced – and it is worth looking at the cause while doing so: too little ventilation, a cracked joint, moisture running behind it or a building silicone without a fungicidal finish.
Can you seal silicone joints afterwards?
There are impregnations for grout, but nothing that makes a silicone surface permanently smooth and dirt-repellent. More effective is the simple routine: squeegee and wipe dry after showering. That prevents more deposits than any product.
How often should you clean silicone joints?
For daily-use showers, give them a quick clean roughly weekly and a thorough one every few months. More decisive than the frequency is squeegeeing and wiping dry after showering – that prevents most deposits before they form.
