First: is it a stain or an etch?
A stain is darker than the stone, or a different color, because something soaked in. An etch is a dull, lighter spot where an acid ate into a calcium-based stone like marble or dolomite. A poultice draws out stains. An etch is damage to the surface and needs polishing; a light one can be buffed with a marble polishing powder, and a deep one needs a stone restoration professional.
How a poultice works
A poultice is an absorbent powder mixed with a liquid that dissolves the stain. Spread on the stone, the liquid soaks in, loosens the stain, and is pulled back out with it as the paste dries.
- Clean the area with water and a stone cleaner.
- Mix the powder and liquid to a thick paste, about like peanut butter.
- Spread it ¼ to ½ inch thick, a little past the edge of the stain.
- Cover with plastic wrap, tape the edges, and poke a few small holes.
- Leave it 24 to 48 hours so it dries completely.
- Scrape it off with a plastic scraper, rinse and dry. Repeat if the stain is lighter but not gone.
- Reseal the spot once it is clean; see sealing stone countertops.
What to use for each stain
| Stain | Looks like | Poultice |
|---|---|---|
| Oil and grease (cooking oil, butter, cosmetics) | Dark spot, often with a soft edge | Baking soda and water, or a poultice powder with mineral spirits or acetone |
| Organic (coffee, tea, wine, fruit) | Pinkish-brown | Poultice powder with 12% hydrogen peroxide; on dark stone, test first, as peroxide can lighten it |
| Rust | Orange to brown, near metal cans or fixtures | A poultice made for iron stains; deep rust often needs a stone professional |
| Water marks and hard water | White ring or crust | Buff with dry #0000 steel wool |
| Ink and marker | Colored mark | On light stone only, hydrogen peroxide; on dark stone only, acetone or lacquer thinner |
Stains on engineered quartz
Quartz is not porous, so stains rarely soak in. Most marks sit on the surface: scrape dried food with a plastic putty knife and clean with mild soap and water or a cleaner the maker approves. Do not use poultices or strong solvents on quartz unless the maker says to.
Common questions
How do you get an oil stain out of granite?
Spread a paste of baking soda and water ¼ to ½ inch thick, cover it with plastic, leave it 24 to 48 hours, then scrape and rinse. Repeat if needed.
Will hydrogen peroxide damage granite?
It can lighten dark stone. Test it on a hidden spot before using it on a dark granite.
Why is there a dull ring on my marble or dolomite?
That is an etch, not a stain: an acid such as lemon, wine or vinegar reacted with the stone. It needs polishing, not a poultice.