Q. What is the best way to clean a white marble bathtub? What is the best way to keep it clean? What shampoos and soaps should be used by people in marble bathtubs?

 

A. The shampoos, soaps, and cleaners you use can damage, stain, or diminish the appearance of your porous, calcium-based marble tub. The safest products to use are pH-neutral and those containing no abrasives, detergents (synthetic cleaners), surfactants (surface active agents), dyes, fragrances, sulfates, or other additives.

 

Acidic and alkaline substances can react with the calcite or other minerals in your marble tub, causing damage that will appear as a rough, white discoloration on the surface. This etch damage can't be cleaned off, so the best approach is to prevent it happening in the first place. 

Dyes or colorants, especially those containing blue, green, or turquoise dyes can darken, discolor, or even permanently stain your marble. Although poulticing can remove most stains, the stain removal process can be messy and time-consuming. Again, you are wise to proactively avoid the problem.

If you are diligent about cleaning the tub with stone-safe, neutral cleaner after each use, you can prevent soap scum buildup, as well.

I checked with Fred Hueston, President of Stone Forensics and Chief Technical Director of SurpHaces, as to whether it would be advisable to seal the stone, and he said, "The problematic thing about sealers is that they won't keep water out of the stone, especially in the deep parts of the tub. My recommendation would be not to seal it, and just keep it clean. Since the impregnators only reduce the pore size of the stone, the sealer will force water inside. It's better to leave it unsealed, and that way, it will dry out faster."

For more information about cleaning and caring for your marble tub, download our free Stone and Tile Care Guide.