black marble soap scum...

Dear Jason:

Are you sure it is soap scum?

In the stone business there's only one instance – and one instance only – when the perceived problem corresponds exactly to the actual problem: when a piece of stone is broken – End of the list. In all other instances, the perceived problem could be the actual problem, but then again, all too often it is not.

To find out if it is indeed soap scum, try to remove some with a razor blade.

If it is soap scum, then you will need a heavy-duty alkaline cleaner with chelates in its formula rated “for natural stone”, like MB-3.

Just keep in mind that soap is acidic (stearic acid) and a two-year accumulation could have caused the marble underneath to etch. If that's the cas e, the etching will appear like a whitish discoloration that will not come out. Only a professional stone restoration contractor will be able to restore your shower stall to its pristine conditions by lightly grinding the surface of the marble (honing) and then polishing it up as close as possible to factory specs.

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 z io Bertoli