I have a large raised hearth made of a single slab of limestone. There are lines and areas of discoloration (lightness and darkness) throughout the surface. The lines somewhat resemble water stains, but I'm not sure. Someone recommended using "Oxy Clean" in paste form to clean it. I tried it, but still have a lot of light/dark variations. What do you recommend to try to make the overall color more uniform?

 

Dear Julie:

Someone tells you to try something and… you just try it!

Never mind that Oxyclean should never get any closer than a ¼ of mile to natural stone – especially calcite-based ones – you just try it out on the mere suggestion from someone… Tsk, tsk, tsk… J

You obviously have marks of corrosions (etch marks) on your stone possible caused by some acidic fluid that was spilled on your stone or the use of inappropriate cleaning agents, and Oxyclean made matters worse, of course.

There's an easy remedy, though. Get an orbital sander (not a belt sander), and starting with a metal-grade sandpaper 60 grit, re-hone the entire surface of your hearth. Once you've done with that grit, go on to 120 and then 240. That should do. You have to spend some time with each grit, to get a very uniform pattern. You could to the job fry, or wet. If you do it wet, there wouldn't be any dust and the sandpaper would last longer; but you'd have a messy sludge to deal with.

If at that point you would like to see a deeper hue in your stone (like when it is wet), then the application of a good-quality stone color-enhancer like MB-6 will give you permanently the “wet-look” (only the depth of color, not any sheen.)

And from now on, when you have a problem with stone, come here – don't just ask “someone”! J

May I ask you now to please read and e-sign our Statement of Purpose at: http://www.marblecleaning.org/purpose.htm?

Ciao and good luck,

Mauri zio Bertoli

 

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