Q. Dear Sir or Madam, We would like to consult you to resolve a problem of lemon stain on a table of black slate. Indeed, it is a table we manufactured with black slate, smooth finishing, on which we apply a water-repellent product Idrobase 303, from FEDERCHEMICALS. While using it, lemon was dropped on the surface and whitish stains appeared. Do you have any suitable product to clean this type of stain on black slate? If yes, following to the cleaning, do you have a protection product to avoid that it happens again? The table is in New York. Do you have any accredited representative or company that can clean the stain and apply the preventive product? We are waiting for your answer in the shortest time, in order to give a quick answer to our customer

 

A. What you are referring to is likely not a lemon stain, nor a problem resulting from the sealer, but an etch mark caused from the acid of the lemon.

 

Some slates do contain calcium carbonite which means, when anything acidic comes into contact with it, may result in an etch mark. Etch marks are dull, whitish areas.

 

The solution: we recommend that you call in a stone restoration / refinishing contractor to abrasively hone out the damaged area. There are several highly qualified contractors in your area. Visit www.stoneandtilepros.com and click on Find a PRO to find one in your area.

 

After it is honed and repaired, it will need to be re-sealed with a good impregnating (penetrating) sealer that repels both oil and water.

 

John Freitag

Director The Stone and Tile School

www.thestoneandtileschool.com