How to remove a water circle stain on limestone?
Estimated Reading Time: 2 MinutesQ. I have a water circle stain on my limestone. How do I remove the stain?
A. Limestone is a porous, calcium carbonate-based stone that is sensitive to acids and moisture. Liquids can absorb into its surface if it's unsealed or the sealer is worn. Acidic substances like juice, vinegar, or harsh cleaners can react with the stone and cause dull, whitish marks known as etching. Because of these characteristics, limestone requires pH-neutral cleaners and regular sealing to inhibit staining.
Just in case the water ring is caused by contaminants on the surface of the stone, clean the area with a stone-safe, pH-neutral stone cleaner. Use a soft cloth or sponge. Let it dry completely.
If the discoloration persists, it's likely etch damage. Water rings on limestone are usually caused by light etching from mildly acidic substances. As long as the damage is not too deep, you may be able to polish it out using a marble polishing compound. Gently buff the area with a soft cloth, following the product instructions. This should work beautifully for polished limestone.
NOTE: If your limestone has a satin/matte finish, this product will create an area that is more polished or reflective than the surrounding stone. A professional stone restoration contractor can resolve this problem. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO.
For deep etch damage, professional honing and polishing will be required.
If your limestone if it hasn’t been sealed recently, ask your PRO to provide this service for you. Using coasters, wiping spills quickly, avoiding acidic foods and drinks on limestone surfaces can help prevent future damage.
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.]