What is the best grout cleaner for a Carrara marble tile bathroom floor?
Never mind - I'm going to try Finazzle for marble.
Here's something that is good for cleaning grout and I shouldn't think it would harm marble - Castile Soap. I buy the liquid Dr. Bronner's soap and mix it with water and use that for cleaning grout. I don't know why but it works very well and it's a natural product so it's pleasant to use.