QUESTIONWhat product can we use to remove cement grout haze from polished marble tile? The tile was sealed prior to grouting with unsanded grout, but has lost it's shine. It's been 3 days now, we've tried cheesecloth, microfiber towels, sponges and hot water, nothing is helping. All the products I'm finding are acidic.
ANSWERANSWER - Normally to remove a cementitious haze you use acid, but not just any acid as acid used wrong can cause etching problems. Never use muriatic acid like what is added to pools. Sulphamic acid is the safest, but you have to dilute it and wet the surface first before applying it. Always test first to make sure the surface isn't too acid sensitive.
Because it is a polished marble made of calcium carbonate it makes it acid sensitive. If it is actually a cement haze, then if you take some diluted vinegar in a out of the way spot and apply it to the haze it should remove it. Of course rinse the spot with clean water right away and wipe dry.
The question is whether the haze is actually a cement haze or a haze from the polymers that are added to cementitious grouts.
There is a neutral based cleaner by Aqua Mix called NanoScrub that can be purchased at Home Depot that claims it cleans most coatings over marble safely. I would try that first.
If all else fails, you can have a qualified professional stone restoration company refinish the marble surface to look like new.