Cleaning and caring for marble

How do you clean marble day to day?

Clean marble with warm water and a pH-neutral cleaner, stone soap or a mild washing-up liquid. The Natural Stone Institute (NSI), the US natural stone trade association, advises rinsing thoroughly after washing and drying with a soft cloth. Too strong a mix leaves a film and streaks, so a small amount is enough.

To deal with a spill:

1. Blot it straight away with a paper towel. Do not wipe, because wiping spreads the spill (NSI).
2. Rinse the spot with water and a little mild detergent.
3. Dry with a soft cloth.

Coasters belong on a marble table, particularly under glasses with alcohol or citrus juice, and hot dishes go on a trivet or mat (NSI). Soap does not lubricate stone or close its pores, as is sometimes claimed; too much of it just leaves a film. When you choose a cleaner, check that the label says it is safe for natural stone. US stone restorer Galen Roth, interviewed by Use Natural Stone, advises leaving on the shelf any everyday cleaner that tells you to test it on a hidden spot first.

The same advice applies to a marble dining table and to smaller pieces such as marble trays and cutting boards. On floors, go over the stone often with a dry dust mop, because sand and grit are abrasive, and mats inside and outside the entrance cut down the grit that gets in (NSI).

What should you never use on marble?

Acidic, abrasive and hydrofluoric-acid products damage marble. The most common culprits:

Never use rust removers or toilet cleaners on marble, not even to remove a stain. NSI recommends steel wool only dry and only in the finest 0000 grade, for water rings and light surface scratches, and even then it is worth trying it on a hidden spot first.

Marble and hydrochloric acid: why does acid etch the stone?

Acid etches marble because marble is calcium carbonate, which dissolves in acid. With hydrochloric acid the reaction is CaCO₃ + 2 HCl → CaCl₂ + H₂O + CO₂: calcium leaves the surface as calcium chloride, which dissolves in water, and carbon dioxide bubbles off (Chemguide). What is left is a dull, often slightly rough spot. The acids in vinegar, lemon and wine etch marble on the same principle.

An etch is caused by a chemical reaction, not by the porosity of the stone. It is not dirt, so it will not wash off, and sealing does not prevent it. A restorer interviewed by Use Natural Stone describes etching as a dull spot or burn mark. He says red wine wiped up straight away rarely stains, but its acids may still etch the surface. Dolomitic marble reacts with acid more weakly than calcite marble (James Madison University), but it should not be exposed to acids either. The chemistry, including the school hydrochloric acid experiment, is explained in our guide to marble properties.

Stain or etch: how can you tell?

A stain is a darker or coloured patch; an etch is a pale, dull spot. The difference decides the fix:

NSI notes that some substances etch without staining and others do both. Red wine, for example, can leave both a colour and a dull ring; remove the stain first, then polish out the etch. Water tells you a lot too: if a drop of water darkens the stone, the stone is absorbing water and the sealer has worn off.

How do you remove stains from marble?

Removing a stain starts with identifying it, because the right chemical depends on what caused it (NSI). Wash the spot with a mild detergent first. If the stain stays, make a poultice to suit the stain:

The advice in the table comes from the NSI stain guide. NSI limits hydrogen peroxide and bleach for ink to light stone, and because both lighten stone, acetone is the safer choice for organic stains on dark marble too.

Rust. NSI’s rust recipe is a poultice of diatomaceous earth and a commercial rust remover, but the same organisation warns that many rust removers contain hydrofluoric acid, which attacks every kind of stone. So do not use rust removers on marble yourself. Deep rust can stain the stone permanently, so leave rust stains to a stone restorer. Prevention works best: do not leave wet metal objects, tins or plant pots standing on the stone.

Using hydrogen peroxide safely. 12% hydrogen peroxide is hair-bleaching strength (NSI), and it is also the strongest a consumer can buy in the EU without a licence: Regulation (EU) 2019/1148 on explosives precursors caps hydrogen peroxide sold to the general public at 12% by weight. It is a stain remover for a small area, not a floor cleaner. Wear gloves and eye protection, ventilate the room when you use acetone or thinners, and never mix ammonia with chlorine bleach.

How to make a poultice, step by step

A poultice is a paste that draws a stain out of the stone as it dries. It is made from an absorbent powder and a chemical that suits the stain. NSI’s method:

1. Choose a powder: kaolin, diatomaceous earth, talc, whiting (powdered chalk) or white moulding plaster. White paper towels or cotton wool also work.
2. Wet the stained area with distilled water.
3. Mix the powder and the chemical into a paste about as thick as peanut butter.
4. Spread it 6-12 mm thick with a wooden or plastic spatula, extending about 2.5 cm beyond the edge of the stain.
5. Cover with plastic and tape down the edges.
6. After about 24 hours, remove the plastic and let the poultice dry completely, usually 24-48 hours in total. As it dries, it pulls the stain into the powder.
7. Remove the poultice, rinse with distilled water and buff dry with a soft cloth.
8. Repeat if needed. A stubborn stain may take up to five applications.

About 0.5 kg of poultice covers about 0.1 m². Do not use whiting or iron-bearing clays such as fuller’s earth with acids. If the chemical has dulled the surface, polish the spot afterwards. NSI is frank that some stains never come out completely.

How do you repair an etch mark?

You can fix a small etch on polished marble yourself. NSI’s method is to wet the surface, sprinkle on marble polishing powder and rub with a damp cloth or a buffing pad on a low-speed drill until the mark disappears and the surface shines. Leave deeper etches to a stone restorer.

Repair kits are also sold. According to its maker, the FILA Marble Restorer kit removes acid marks and restores the shine on small polished marble, travertine and limestone surfaces such as tables and worktops. The surface is rubbed wet with three pads in a set order and then finished with a polish. The maker says one kit covers about 1.5 m² with up to 30 damaged spots 6-7 cm across, and that it is not for floors, granite, quartz composites or acid-resistant stones such as Verde Alpi.

What is a marble polish?

Marble polishing products are usually powders or pastes, often based on oxalic acid or potassium oxalate. Stone care sources warn that they may harm green and maroon stones and can build up on the surface if overused. Test a polish on a hidden spot first and use it only where you need it, not on the whole surface every week.

Should marble be sealed?

Sealing (impregnating) marble is worth it on surfaces that see oil, coffee or wine, because it slows down staining. It does not protect against acid etching. NSI points out that stone sealers are really impregnators: they repel liquids but do not seal the stone, and they make it more stain-resistant, not stain-proof. NSI adds that many stones do not need sealing at all and that you should ask your stone supplier. In a food preparation area, use a non-toxic product.

A staining test by the sealer maker FILA, run to standard UNI EN 16301, shows the effect clearly. On untreated Carrara marble, oil caused a moderate change within an hour and a strong change within four hours, while coffee caused a strong change within the first hour. On the surface treated with FILA’s MP90 ECO XTREME, neither caused any change. The maker says the protection takes effect after 24 hours and treated surfaces are safe for food contact, but the product does not protect against acid.

Scale: 1 = no change, 2 = slight, 3 = moderate, 4 = strong change (FILA).

How often should marble be resealed?

There is no single right interval, so test instead of going by the calendar. Of the restorers interviewed by Use Natural Stone, one reseals every 9-12 months and another every 5-10 years, and sealer lifespans are quoted from 6 months to over 10 years. The water drop test tells you where you stand:

1. Dry the surface.
2. Put a few drops of water on a spot that sees normal use, not right at the edge.
3. Wait 15 minutes without wiping.
4. If the drops stay round, the sealer is working. If the water spreads but the stone does not darken, the sealer is partly worn: test again in a few months. If the stone darkens under the drop, reseal now.
5. Test oil separately with a drop of cooking oil.

Test several spots, because the sealer wears first near the sink and hob. Do not apply new sealer over a sealer that still works: it cannot soak in and dries on the surface as a hazy film. A good routine is to test after installation, again after six months and then once a year.

Always seal according to the maker’s instructions. FILA, for example, advises applying its product to a clean, dry surface with a brush or applicator pad and, on polished stone, working it in with a microfibre cloth before it dries, after roughly 10-15 minutes, then drying the surface with a clean cloth. Try any sealer on a small area first to check that it does not change the colour.

Honing and polishing: DIY or professional?

Leave honing to a stone restorer when scratches and etches are deep or the whole surface has gone dull. You can polish small etches yourself with polishing powder and lightly buff surface scratches with dry 0000 steel wool, but NSI advises having deeper scratches and nicks repaired and re-polished by a professional.

Polished and honed surfaces behave differently. A restorer interviewed by Use Natural Stone says etching shows more on polished marble than on honed or textured marble, and he estimates that heavily used polished marble needs refinishing every 2-3 years and honed marble every 3-5 years. That is why many people choose a honed finish for a kitchen; read more about marble kitchen worktops.

Another restorer points out that marble can be refinished an almost endless number of times. There is no fixed depth that honing removes, such as the 2 mm sometimes quoted: refinishing takes off as much as the depth of the damage requires. Sanding at home is risky. Starting with coarse paper, such as P80, cuts deep scratches into a polished surface that then have to be worked out with ever finer grits, and an even shine across a large surface takes machines and experience. A table or worktop made to your measurements is therefore worth restoring in place rather than replacing.

Marble crystallisation: what is it, and does it suit a table?

Marble crystallisation (kristallointi in Finnish) is a maintenance method for polished calcium-based floors, not a way to care for tables or worktops. A liquid containing acid and, most often, magnesium fluorosilicate is sprayed on and buffed in with a steel-wool pad under a weighted floor machine. Friction heat drives the reaction: the acid etches the calcium carbonate and the fluorosilicate binds the released calcium into calcium fluorosilicate (CaSiF₆). The new layer is harder, glossier and more stain-resistant than the original surface.

Crystallisation has been used since the 1960s and is still controversial among stone care professionals. What is known:

• The change is chemical and permanent. The layer can only be removed mechanically, for example by diamond honing.
• The method is meant only for polished surfaces, not honed ones.
• A hard new layer over softer stone can delaminate, especially in stones that contain carbon, and iron from the steel wool can get into many porous limestones.
• Opponents say the layer stops the stone from breathing and traps moisture.
• The US trade body Marble Institute of America neither condemns nor endorses the process.

Chemist Frederick Hueston, an opponent of the method, reports that every product he examined contained a fluorosilicate and an acid, and most also contained waxes or acrylics. According to Hueston, a drop of crystallisation fluid etches marble within 30 seconds, travertine and Crema Marfil are damaged almost immediately, and fluorosilicates were tried on crumbling marble statues as early as 1883, with later studies finding them harmful to stone. His advice is blunt: if a product contains fluorosilicates, do not use it.

The layer that crystallisation creates is calcium fluorosilicate, not calcium silicate as is sometimes claimed. For tables, worktops and vanity tops the method is the wrong tool, because it is an acid treatment done with a floor machine. Their shine is restored by honing and polishing.

Cleaning white marble

Clean white marble the same way as any other marble, but expect coffee, tea, wine and rust to show most on a light surface. On the other hand, light stone can take treatments that dark stone cannot: 12% hydrogen peroxide works on organic stains and ink, and bleach on ink too (NSI). Our guide to marble types and colours covers how white marbles differ.

With white marble in particular:

• Wipe up coffee and wine at once: in FILA’s test, coffee caused a strong change on unsealed Carrara marble within an hour.
• Do not leave wet metal objects or tins on the stone, because rust takes hold on pale stone and deep rust can be permanent.
• Keep a saucer under plant pots: metal parts on a pot can leave rust, and fallen leaves leave organic stains.
• Seal a white worktop or dining table and do the water drop test regularly.

Marble in the bathroom and outdoors

In the bathroom, marble’s enemies are soap scum, acidic descalers and toilet cleaners. NSI recommends using a squeegee on wet surfaces after each use to keep soap scum down. Soap scum can be removed with a non-acidic soap scum remover or a solution of ammonia and water, but frequent use of ammonia may dull some stones. Descalers are not suitable for marble, and toilet cleaners should be kept away from the stone altogether because they may contain hydrofluoric acid. Creams and make-up leave oil-based stains, which come out like any oil stain. For vanity tops, see marble for the bathroom; for floors and walls, see marble tiles.

A white powder called efflorescence can appear on a newly laid stone floor. NSI advises against washing it off with water, because it only disappears for a while. On a new installation, vacuum it or use a dry dust mop.

Outdoors, marble is an unusual choice in Finland: the Finnish Natural Stone Association’s materials guide says it copes poorly with temperature swings and loses its polish. If you do have marble outdoors, NSI advises flushing it with clear water and removing algae or moss with a mild bleach solution.

Marble care checklist

The marble we use comes from Iran, and since marble is always a carbonate stone, all of this advice applies to it as well. Our Iranian marble page describes the stones that come from there. Everyday care fits on one list:

• Blot spills straight away with a paper towel; do not rub.
• Use coasters, mats under hot dishes and a cutting board.
• Wash with a pH-neutral cleaner, rinse and dry.
• Never use vinegar, lemon, descalers, rust removers, toilet cleaners or scouring powders.
• Never mix ammonia and chlorine bleach.
• Do the water drop test after installation, after six months and then once a year.
• Keep metal objects and plant pots on a saucer.
• Leave deep scratches, deep etches and rust stains to a stone restorer.

If you are still deciding which stone and finish suit the way you live, tell us in your quote request and we will suggest options.