Material
Grout
Porous alkaline cement between tiles, dissolved by acid, easily made worse by hard brushing, and best protected by sealing.
- SurfacePorous
- WashingSpot only
- Colour run riskLow
- Reviewed7 September 2026
What grout can and cannot take
- Heat Use with care
- Water and soaking Tolerates it
- Acids, including vinegar Avoid
- 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 grout
Grout is a porous cement that sits slightly below the tile face, which means it catches everything and is hard to reach.
Use a mildly alkaline or neutral cleaner and a soft brush along the joint. Acid is excluded because it dissolves the cement, and the damage shows as a soft, crumbly, more absorbent joint that stains faster next time.
Rinse properly. The trade body warns that alkaline cleaner left behind leaves a sticky residue that attracts dirt, which is how a cleaned floor gets dirty again quickly.
Check the label
Cementitious grout is alkaline and porous, and the tile trade body states plainly that acids attack the cement in grout and dissolve it. Mildly alkaline cleaners are preferred, alkaline cleaner that is not rinsed properly leaves a sticky residue, and sealing is what prevents staining in the first place.
Stains on grout
- Baby sick Work along the joint with a soft brush and warm soapy water, and for anything stubborn use a bicarbonate of s...
- 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 grout, 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 grout before it is rubbed in. Blot cream bronzer, follow the material or care label,...
- Coffee Wipe coffee off grout promptly with a soft cloth. Identify stone, sealer and adjacent grout before choosing e...
- Concealer Lift the concealer from Grout, clean with neutral stone cleaner or very dilute washing-up liquid, rinse and d...
- Cooking grease Blot cooking grease from Grout, absorb surface oil, wash gently with mild detergent and judge when dry. A rem...
- Deodorant Lift loose deodorant from grout with a dry white cloth, then wipe the remaining film with cool water and one...
- Hair dye Blot hair dye from Grout, test the mildest compatible cool detergent route, clean inwards, remove residue and...
- Lipstick Lift lipstick from Grout, clean with neutral stone cleaner or very dilute washing-up liquid, rinse and dry. A...
- Motor oil Blot motor oil from Grout, 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 grout can tolerate. Use a labelled pet urine enz...
- Tomato sauce Lift tomato sauce from Grout, then wipe or blot inwards with a tested cool detergent solution. Remove residue...
Grout is a cement based filler between tiles, and it is the porous part of an otherwise non porous surface.
Acid dissolves it
The tile trade body is explicit: grout is alkaline based and is dissolved by acids, and grout manufacturers do not advocate their use. Acid on a grout line removes cement, leaving a joint that is softer, rougher and more absorbent than it was.
Hard brushing does the same thing mechanically
A wire brush or an abrasive pad takes the surface off the joint. Cleaner grout that absorbs faster is not an improvement.
Residue is a real problem
Alkaline cleaner that is not rinsed out leaves a sticky film in the joint that attracts dirt, which is why a floor sometimes looks worse a week after being cleaned.
It is renewable
Raking out the top few millimetres and refilling is a normal job and it produces a result that no cleaner can. That is the honest end point for badly stained grout.
Sources
What we checked and when. Where a manufacturer instruction disagrees with anything here, follow the manufacturer.
-
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
-
Quarry tile care and maintenance, Daltile
manufacturer
Tile manufacturer guidance that quarry tile is sealed before grouting and resealed regularly to protect against staining, that routine cleaning is multi purpose products or plain soap and water, that no rinse enzymatic and acid based cleaners are avoided because the combination of heat, food contamination and cleaner makes the grout soft and permanently damages it, and that a soft bristle brush suits the textured surface.
Checked 7 September 2026
-
Terrazzo maintenance, National Terrazzo and Mosaic Association
trade body
Terrazzo trade body guidance to clean with a neutral product between pH 7 and 10, that harmful acids and alkalis damage terrazzo, that all purpose cleaners and soaps containing water soluble or crystallising salts should be avoided, that sand based compounds abrade the floor, that solvent based sealers discolour with age, and that spills need immediate cleanup because terrazzo stains.
Checked 7 September 2026