How to remove widespread, deep etch damage from a marble floor?

Q. My housekeeper put straight vinegar on my shiny black marble floor on the entry way only to my bedroom & bathroom. I have ordered an etch removal product. Is this all I need? What else will I need to do? Should I sand the etched area?

A. Because vinegar is an acid and polished black marble is calcium-based, the damage you’re dealing with is etching, not staining. Obviously, you were on the right track, when you ordered an etch removal product. You've probably noticed that the acid has actually dissolved part of the marble’s surface, leaving it dull and uneven.

Since the vinegar was used straight and spread over a walking path, we will assume the etching is widespread and deep. Unfortunately, if you try a DIY etch removal product on extensive etch damage, it is unlikely to fully solve the problem. Etch removers are essentially light polishing compounds designed to treat small, shallow etches.

Were you to use this product, what would happen is you would polish one etched area and then run into difficulty blending the finish of the treated area with the surrounding marble. You the etched area would look glossier, duller, or slightly different in texture than the rest of the floor. 

You mentioned sanding. Marble restoration is an art and a science that requires a precise sequence of diamond abrasives followed by mechanical polishing. Using sandpaper or aggressive pads could introduce scratches that go deeper than the original etching, expanding the damaged area. 

We highly recommend you contact a professional stone restoration contractor to hone and polish the marble to restore an even, high-gloss finish. This process removes the etched layer uniformly rather than trying to spot-fix isolated areas. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO. Your PRO will have the tools to control gloss level, match the original finish, and avoid creating visual inconsistencies.

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.]