How to remove toothpaste residue from limestone bathroom countertop?
Estimated Reading Time: 3 MinutesQ. Our bathroom countertops are dark grey Limestone. There is a 4 inch round white stain on the countertop beside the sink. I THINK IT IS TOOTHPASTE RESIDUE. We are listing our house for sale this week and the stain needs to disappear ASAP.
A. Limestone is a relatively soft, porous calcium-carbonate stone. Bathroom countertops made from limestone react easily to moisture, cosmetics, toothpaste, and cleaning products. Dark grey limestone tends to make light marks stand out more clearly. Since you strongly suspect the discoloration you describe is toothpaste residue, let's move forward with the assumption that your hunch is correct.
Toothpaste can leave a white spot because its ingredients include mild abrasives, detergents, or whitening agents like hydrogen peroxide, plus binders that can dry into a light-colored film. Every now and then, a toothpaste brand will contain slightly acidic compounds. When a blob of toothpaste sits on limestone and dries, it can leave a chalky, circular mark.
You'll find that problem to resolve the fastest and easiest is if the toothpaste residue is on the surface of the stone. Clean the area with warm water and a few drops of mild dish soap using a soft cloth. If the mark doesn’t lift right away, you can apply a simple poultice of diatomaceous earth and water, leave it overnight, and rinse. A poultice draws the stain out of the stone over time. For detailed, step-by-step instructions on how to mix and apply a poultice correctly, check out our free Stain Management App. This is safe for limestone and often enough to soften dried toothpaste or soap scum. After removing the poultice, clean the area with stone-safe, pH-neutral cleaner.
If the mark doesn’t change at all with cleaning, or if it stays just as white when the stone is wet, toothpaste could still be involved, but as an acid source rather than a residue. For the record, this type of discoloration is an etch, not a stain, and it's not something one can simply wipe away. Some toothpaste formulas, mouthwashes, and cosmetic ingredients are acidic enough to etch limestone, meaning they dissolve a thin layer of the stone and leave a dull, lighter patch.
Regardless of what caused the etch, light etch damage can usually be blended with the surrounding stone using a stone-safe polishing powder or cream made for marble or limestone. If your countertop is honed, the area you work on could end up looking more reflective than the surrounding area. Polishing out an etch works best on polished stone surfaces. These products gently re-polish the etched area so it matches the surrounding surface. For deep etch damage or if you have countertops with a satin/matte finish, hire a stone restoration contractor to refinishing your top. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO.
Other causes are possible too. Hard-water mineral deposits, acidic or bleach-based cleaners, peroxide-containing cosmetics, or even an overly aggressive scrubbing could have dulled the finish.
ABOUT THE AUTHOR Fred Hueston is the Chief Technical Director at SurfaceCarePROS.com and Director at StoneForensics.com. He is also the author of Stone and Tile Restoration: The Manual, a comprehensive online manual for stone and tile restoration contractors. [Learn more about Fred.]