Material
Slate
A siliceous stone with a riven textured face that holds a spill in its hollows, and usually a sealer or an oil dressing that strong cleaning strips.
- SurfaceSemi porous
- WashingSpot only
- Colour run riskLow
- Reviewed7 September 2026
What slate can and cannot take
- Heat Use with care
- Water and soaking Use with care
- Acids, including vinegar Use with care
- Strong alkalis Use with care
- Solvents Use with care
- Chlorine bleach Use with care
- Abrasives Use with care
Always test on a hidden area first and let it dry before you treat the visible mark.
General rules for slate
The texture is the problem rather than the chemistry.
A riven slate face has hollows that hold liquid where a cloth cannot reach, so blotting has to be pressing rather than wiping, and a soft brush is genuinely useful on slate where it is not on a polished stone.
Be careful with the finish. Many slate floors are sealed with a topical sealer or dressed with slate oil, and detergent strips both, leaving a patch that looks lighter and drier than the rest.
Check the label
Slate is siliceous and reasonably acid resistant, but its riven surface is the complication: a natural cleft face is full of ridges and hollows that hold a spill and are almost impossible to wipe clean. Most slate floors are also sealed or oiled, and strong cleaning strips that.
Stains on slate
- Baby sick Press kitchen roll into the riven surface rather than wiping across it, because the hollows in a cleft slate...
- Blood Blot first, then use cold water and a tiny amount of compatible detergent. Work from the edge, rinse or blot...
- Body oil Lift free oil from slate, then clean a small area with a maker-approved mild detergent solution and a soft cl...
- Breast milk Blot the spill, identify the finish and use a controlled cold clean only where permitted. Where the maker per...
- Bronzer Lift loose bronzer from slate before it is rubbed in. Blot cream bronzer, follow the material or care label,...
- Coffee Wipe coffee off slate promptly with a soft cloth. Identify stone, sealer and adjacent grout before choosing e...
- Concealer Lift the concealer from Slate, clean with neutral stone cleaner or very dilute washing-up liquid, rinse and d...
- Cooking grease Blot cooking grease from Slate, absorb surface oil, wash gently with mild detergent and judge when dry. A rem...
- Deodorant Lift loose deodorant from slate with a dry white cloth, then wipe the remaining film with cool water and one...
- Hair dye Blot Slate, clean with a tested non-acidic stone product, rinse and dry. Refer absorbed colour rather than im...
- Lipstick Lift lipstick from Slate, clean with neutral stone cleaner or very dilute washing-up liquid, rinse and dry. A...
- Motor oil Blot motor oil from Slate, absorb surface oil, wash gently with mild detergent and judge when dry. A remainin...
- Nail polish Lift free polish gently if the face permits contact. A maker-approved mild damp wipe can clear loose residue,...
- Period blood Lift any tissue with a spoon edge, then blot. Use cold water and a tiny amount of compatible detergent for th...
- Pet urine Blot until nearly dry, then use only the cool-water quantity slate can tolerate. Use a labelled pet urine enz...
- Tomato sauce Lift tomato sauce from Slate, then wipe or blot inwards with a tested cool detergent solution. Remove residue...
Slate is a fine grained metamorphic rock that splits into sheets, which is why it is used for flooring and hearths.
The surface is uneven by design
A riven face is the natural cleft, full of small ridges and hollows. Liquid sits in them and a flat cloth passes straight over. That is why slate needs pressing and brushing rather than wiping.
The chemistry is straightforward
Siliceous, so acid is a precaution rather than an absolute, though the trade body still advises against acidic cleaners.
The finish is what you strip
Sealed and oiled slate looks darker and richer than bare slate. Detergent takes that off in the area you clean, so a treated patch can end up visibly lighter even when it is perfectly clean.
It flakes
Some slate delaminates at the surface, and scraping at a mark can lift a flake.
Sources
What we checked and when. Where a manufacturer instruction disagrees with anything here, follow the manufacturer.
-
Care and cleaning of natural stone, Natural Stone Institute
trade body
Stone trade body guidance that calcareous stone such as limestone and travertine is sensitive to acid so only mild non acidic cleaners are used, that acidic cleaners are still not advised on granite, slate or sandstone because they can hold acid sensitive minerals, that scouring powders scratch stone, that the routine clean is a neutral cleaner or mild washing up liquid in warm water, that organic stains are treated with hydrogen peroxide, and that ammonia and bleach are never mixed.
Checked 7 September 2026
-
Guide to cleaning marble stains with poultices, Olson Marble and Stone Care
specialist
Stone restoration specialist describing a poultice as an absorbent powder mixed with a cleaning agent, bicarbonate of soda with hydrogen peroxide for an organic stain, spread about a quarter of an inch thick, covered with plastic wrap taped down and left for 24 to 48 hours, that stubborn stains need more than one application, and that a stone that is deeply etched or discoloured beyond surface penetration needs professional restoration rather than a poultice.
Checked 7 September 2026
-
Cleaning grout, Tile Council of North America
trade body
Tile trade body guidance that grout manufacturers do not advocate the use of acids because acids attack the cement in the grout, that grout is alkaline based and is dissolved by acids, that mildly alkaline cleaners are preferred over acidic ones, that oil and wax based cleaners leave a film that attracts dirt, that alkaline cleaner not properly rinsed leaves a sticky residue, and that cementitious grout should be sealed to prevent staining.
Checked 7 September 2026