Prep first
Before you start
- Work out the cause before you reach for a cleaner.
- Test any cleaner on a hidden spot first.
- Hold off on chlorine bleach until you know the mark isn't manganese or iron, since bleach can intensify those stains.
- Start with brushing and warm soap, and save the solvents for oil and ink.
Black marks on granite describe a color, so the cause could be mildew, soot, manganese from well water, rubber from heels or tires, or greasy residue. Fresh oil or ink usually responds to a solvent, while an old stain may need a poultice that sits under plastic for a day or two. Some stains may never be completely removed, and deep rust or copper marks are more stubborn still.
Reach for a stone-safe, pH-neutral cleaner before anything harsh, since that's what protects the polish. For dark stains on granite countertops, a poultice is the right tool for a deeper mark, but test it in a hidden corner first. If the mark still shows after a full round, call a stone professional instead of scrubbing harder.
Before you start
What granite can take
Safe to use1
- Water
Use with care6
- Hot water
- Chlorine bleach
- Oxygen bleach
- Solvents (alcohol, spot removers)
- Acids (vinegar, lemon)
- Heat, once the stain is out
Avoid1
- Scrubbing and abrasives
10 items
What you'll need
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- Soft brush or vacuumLifts dry soot and mildew before anything gets wet. (opens Amazon)
- Mild dish soapLifts surface marks and light grease in warm water. (opens Amazon)
- Soft clothsDry the spot without scratching the polish. (opens Amazon)
- Mineral spiritsLifts oil, grease and cosmetics from the stone. (opens Amazon)
- AcetoneHandles oil and the ink or marker on dark stone. (opens Amazon)
- Lacquer thinnerFor ink or marker on dark stone. (opens Amazon)
- Baking sodaForms the poultice paste for oil that remains. (opens Amazon)
- Powdered poultice materialAn alternative poultice, mixed with mineral spirits.
- Plastic wrap and tapeHolds the poultice in place for 24 to 48 hours. (opens Amazon)
- Plastic scraperRemoves the dried poultice without scratching the stone. (opens Amazon)
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6 steps
Step by step
Step 1 of 6
Work out what made the mark
Check where the mark sits, how it smells and feels, and how it appeared. A greasy sheen or smear points to oil, a musty smell or fuzzy patches point to mildew, and powdery black dust points to soot. Sharp black streaks often come from rubber heels or tires, and black marks that show up around well water can be manganese.
Step 2 of 6
Brush off dry soot and mildew
Brush or vacuum any dry soot or mildew before anything wet touches the spot. Brush mildew off outdoors so the loose particles don't end up back on your floors.
Careful. Wetting soot or mildew before brushing it off spreads it over the stone.
Step 3 of 6
Wash the spot with mild soap
Blot up any spill, then flush the spot with warm water and a little mild dish soap. Rinse well with clean water and dry the stone with a soft cloth.
Tip. Work from the outside of the mark toward the middle so the wash doesn't spread the color.
Step 4 of 6
Lift oil or ink with a solvent
For grease, cooking oil or cosmetics, clean gently with mineral spirits or acetone. For ink or marker on dark stone, use lacquer thinner or acetone and wipe as soon as the ink starts to lift.
Careful. Solvents are harsh on skin and lungs, so wear gloves and keep the room ventilated.
Step 5 of 624 to 48 hours
Poultice what the solvent leaves
If an oil stain is still there, mix baking soda with water into a thick paste, or mix a powdered poultice material with mineral spirits. Spread it over the stain, cover it with plastic taped at the edges, and leave it for 24 to 48 hours.
Careful. Keep acid chemicals out of the poultice, because the reaction cancels it out.
Step 6 of 6
Rinse, dry and check the stone
Scrape off the dried poultice with a plastic scraper, then wash the spot with the soap wash, rinse and dry. If the mark is lighter, repeat the poultice; if it hasn't changed, the stain may be set in.
If you'd rather buy than mix
Best products for black stains on granite
Pick a powdered poultice material made for stone, and buy mineral spirits or acetone from a hardware store with the label checked for use on stone.
Granite Gold® Daily Cleaner
Aqua Mix® Poultice Stain Remover
How we picked these: each product is made for this type of stain, its maker doesn't warn against using it on granite, and its directions fit the steps above.
Finished the steps? How does it look?
Nice work. Let it dry completely and check it again in good light. Here is what done looks like:
How to tell it's really gone →A faint mark usually needs one more round, not a stronger product.
Heavy buildup usually takes more than one round.
Heavy or long-standing buildup →When to call a professional →How to tell it's working
Dark spots that lighten after the soap wash or the solvent are on the right track. A poultice that draws color out of the stone over 24 to 48 hours is working, even if the change is slow.
What changes for yours
Adjust for your granite
Dark on granite countertops and counters
On a countertop the steps stay the same, but start with the soap wash and only move to a solvent if the mark is ink or grease. Keep the solvent on the spot just long enough to lift the mark, then wipe it away.
Kitchen counters often pick up cooking oil near the stove, so a dark spot there is usually grease. Work from the soap wash to the solvent before you reach for a poultice. A poultice on a counter needs its plastic taped tight so it doesn't dry out early.
Getting dark out of granite worktops
Worktops are the same stone as countertops, so the methods don't change, only where you work. Because a worktop often sits against a wall or sink, clean from the open side so the cleaner doesn't run into the joint.
Check the edges and the seam by the sink for black mildew, since damp spots collect there. Brush it dry first, then use the soap wash and rinse well so no soap film stays in the joint.
Heavy or long-standing buildup
Old stains that have soaked into granite need more than one pass, because a poultice draws the mark out over time rather than wiping it off. Keep the poultice under plastic for the full 24 to 48 hours and don't rush it. A stain that has been there for years usually needs the longest soak.
If the mark is still there after one application, repeat the poultice. Up to five applications is the limit for difficult stains, and each round should lighten it a little more. Dried-in oil is the stubborn kind and can take several rounds.
Some stains may never be completely removed, and deep rust stains can be permanent. Manganese marks from well water keep coming back until the water is dealt with, so cleaning alone won't stop them. What is left after several rounds is usually as good as it gets.
Vinegar, baking soda, peroxide and more
Do home remedies work on black stains on granite?
Most household remedies are built for fabric, painted surfaces or fresh spills. On granite, only the mild soap wash and the baking soda poultice from these steps apply to dark marks, and the rest either don't suit the stone or don't help with dark stains.
Works2Skip3Avoid1
What makes it worse
Mistakes to avoid
Don't use vinegar or other acidic cleaners
Granite can contain acid-sensitive trace minerals, and acid can dull or etch the polish. Stick to the soap wash and the solvents named in the steps.
Don't scrub with scouring powder or pads
Scouring powders, creams and scrub pads act as abrasives and can scratch the stone. A soft cloth and the soap wash do the job without leaving marks.
Don't mix bleach and ammonia
Mixing the two gives off a toxic gas that can be lethal. Never mix bleach with acids such as vinegar either, and rinse thoroughly between products.
Don't use cleaners that aren't made for stone
Improper cleaners break down the sealer, which is what keeps stains out of the stone. Only use cleaners labeled for stone, since others can break down the sealer that keeps stains out.
When to call a professional
Call your stone supplier, installer or a restoration specialist for stains that resist poulticing, deep rust or copper stains, deeper scratches and nicks, and etching you can't polish out. Ignored water buildup and dull areas around sinks call for stone restoration too.
Questions
How do you clean dark spots on granite?
Start with the gentlest method that fits the cause: brush off dry soot or mildew, then wash the spot with warm water and mild dish soap. Oil and ink need the solvent step, and anything left after that needs a poultice that sits for 24 to 48 hours.
Are black spots on granite mold?
Sometimes. Mildew shows up as fuzzy or musty patches, usually in damp areas, and it needs brushing and washing first. Dark spots that don't respond to washing are more likely to be oil, manganese or damage.
Why do black spots keep coming back on granite?
Usually the cause is still active. Manganese from well water returns until the water is dealt with, and damp spots keep growing mildew. Fix the source, or the mark will keep reappearing after cleaning.
Can a black mark permanently damage granite?
Most dark marks sit on the surface or in the sealer and lift with cleaning. Some are damage rather than dirt, and deep etching or nicks may not lift completely.
How long does a poultice need to work?
A poultice usually sits 24 to 48 hours under plastic. Repeat it up to five applications for a difficult stain, and expect that some marks may never be completely removed.
Is mineral spirits safe on granite?
Yes, when used as described, since mineral spirits and acetone are the solvents for oil on this stone. Test a hidden spot first, keep the room ventilated, and wear gloves.
Do black rubber marks from heels or tires come off granite?
They often respond to the soap wash. If they stay, move to the solvent step, and keep the solvent off the surrounding stone.
Black Stains on other materials
Other stains on granite
Start from the bigger picture
How we know this
Every method, amount and warning here comes from university extension services, industry bodies and product makers. We read them, check every step for unsafe combinations and changed amounts, and write it up so you can follow it.