I've read that a mixture of caustic soda and water over 60 minutes will remove the stains. Is there a process you would suggest? The tile is black marble and has white cloudy spots where the water sits while drying.

Dear Mark:

 

“ I've read that a mixture of caustic soda and water over 60 minutes will remove the stains. ”

 

You read so many things (especially on the internet), don't you?... J

Did you also ever read this?

 

“ A stain – a real stain – is always darker than the stained material. If it is lighter, it's either a mark of corrosion created by an acid (etching), or a caustic mark created by a base (bleaching). There are no known exceptions to this rule. In the case of natural stone, bleaching can't occur, and therefore they are etch-marks all the time: plain and simple surface damages, like shallow chemical scratches. ”

 

Well, if you didn't before, now you did. And now you know that what you have are not stains at all – no matter what they look like.

The caustic soda and water thing is a poultice (and in the case of marble a very wrong one!) designed to pull true stains out from stone. Example: imbedded coffee or cooking oil, and other stuff like that.

Most likely, if the etching is not too severe, you may be able to remove your “stains” with a consumer-grade marble polishing powder like MB-11 (assuming that your marble is polished). If it hone-finished instead a few different grits od good ol' metal grade sandpaper will do the job for you. (Start with 120 and finish at either 240 or 400 grit.)

After that, I believe that's time for you to get some real (specific) intelligence on how to properly care for your stone. By logging into the Helpful Hints section of our website at: http://www.marblecleaning.org/helpful-hints.htm, you will be able to get the short version of our maintenance guidelines at no charge. The full version of it – a 7-page document considered by many as an industry benchmark – is available in pay-per-download format in our Educational Literature section at: http://www.marblecleaning.org/literature.htm.  

And remember, every single penny of the cost of the literature will be used to support this site and its cause: your cause.

While you are in the “Helpful Hints” section, do spend some time reading all of the interesting FREE articles you'll find in there!

Finally, keep in mind that we need your support to help us helping you!

Will you please read and e-sign our Statement of Purpose at: http://www.marblecleaning.org/purpose.htm?    

By spreading the word about this valuable site among your friend & family and the stone trades' people you've been dealing with, you will be rendering everybody a valuable service!

Thank you  

Ciao and good luck,

Mauri z io Bertoli

 

www.marblecleaning.org – The only Consumers' Portal to the Stone Industry Establishment!