How to Get an Oil Stain Out of a Granite Countertop

A dark spot next to the stove, a ring where the olive oil bottle sat, a patch where someone set down a greasy pan. On granite, these are usually oil, and they usually come out.

The steps below come from the Natural Stone Institute, the trade group for the natural stone industry, and from the stone supplier MSI. Start with the gentlest step and only move on if the spot is still there.

How to Tell It Is Oil

The Natural Stone Institute says “An oil-based stain will darken the stone and normally must be chemically dissolved so the source of the stain can be flushed or rinsed away.”

So an oil stain looks like a darker, wet looking patch that does not dry out. The Institute lists the usual causes as grease, tar, cooking oil, milk and cosmetics. Hand lotion and butter count too.

If the spot is dull or lighter instead of darker, it is probably not oil. Our stain guide covers the other kinds.

A Fresh Spill: Cornstarch

If the oil just hit the counter, blot up what you can with a paper towel. Do not wipe, because wiping spreads it.

Then MSI says: “If the stain is a grease stain, just sprinkle on the corn starch, let sit for 15 minutes, then clean it with soapy water.”

Cornstarch soaks up oil that has not had time to sink in. For many fresh spills, that is all it takes.

An Older Spot: Try a Cleaner First

For a stain that has set, the Natural Stone Institute’s first step is to “Clean gently with a soft, liquid cleanser with bleach OR household detergent OR ammonia OR mineral spirits OR acetone.”

Pick one of those, not several. The Institute warns in capital letters: “DO NOT MIX AMMONIA AND BLEACH! THIS COMBINATION CREATES A TOXIC AND LETHAL GAS!” If one product does not work, rinse the spot well with plain water before you try another.

A Stubborn Spot: Make a Poultice

A poultice is a paste that pulls a stain back out of the stone as it dries. For oil on granite, the Natural Stone Institute says to “Poultice with baking soda and water OR one of the powdered poultice materials and mineral spirits.” Baking soda is the one most people already have.

Here are the Institute’s steps, in order.

Mix it. Mix the powder with the liquid “to a thick paste the consistency of peanut butter.”

Wet the spot. “Wet the stained area with distilled water.”

Spread it. Spread the paste about 1/4 to 1/2 inch thick, and “extend the poultice beyond the stained area by about one inch.” The Institute says to use a wood or plastic scraper.

Cover it. “Cover the poultice with plastic and tape the edges to seal it.”

Let it dry. “Allow the poultice to dry thoroughly, usually about 24 to 48 hours.” The Institute says the drying is what pulls the stain into the paste. After about 24 hours, take the plastic off so it can finish drying.

Remove it. “Rinse with distilled water and buff dry with a soft cloth.”

Repeat if needed. “It may take up to five applications for difficult stains.”

The Simpler Version From MSI

MSI’s recipe skips the special powders. It says to “Mix a paste of baking soda and water that has the consistency of sour cream,” spread it on the stain, and cover it with plastic wrap. Then “Let set for 24 hours, then remove the poultice, and clean the area.”

An older MSI guide uses dish soap in place of water: “Oily stains that have soaked into the surface may be removed by applying a paste made with baking soda and dish soap.” It says to let that sit overnight under plastic wrap, then rinse.

Both use the same idea: a paste that dries and pulls the oil out. MSI’s paste is a little thinner, like sour cream, and the Institute’s is thicker, like peanut butter.

When It Will Not Come Out

Be patient with a poultice. Five tries is normal for a deep stain. Still, the Natural Stone Institute is honest that “some stains may never be completely removed.”

Call us if the spot has not moved after a few tries, if the poultice left a dull patch, or if you are not sure what the stain is. A phone call costs nothing.

How to Keep Oil Off Your Granite

Wipe oil and grease spills right away.
Keep oil bottles on a small tray or a plate, not on the bare stone.
Keep the seal in good shape. We seal every natural stone slab before we install it. Sealing makes stone slower to stain, not stain proof.