staines on marble

["Charles Kibby" <ckibby@zzzzzzzzzzz>]

I really like your idea of using a solvent and a drawing agent to clear the
stains frome these tiles..............

Craig:

George is right about the poulticing idea for silicone-based staining
agents, and there are a couple of other things you might use to help.  We
use poultices quite often in our work, and the basic theory is the same
whether one is practicing homeopathic medicine or masonry restoration: a
netural carrying agent holds the cleaning agent in direct contact with the
base material long enough for the cleaning agent to be abosrbed by the
stone, breakdown the staining agent, and then, hopefully, all will be drawn
to the surface to be absorbed fully by the poultice material.  Poulticing is
all too often like alchemy, sometimes the magic works and sometimes it
doesn't........

I have used many different poultice agents, among them plaster of paris (too
messy), pulp fiber (mixed with de-ionized water to remove alkaline salts
 from limestone), and blotter paper or paper towels (when nothing else was
available). My medium of choice is diatomaceous earth, available as swimming
pool filter medium and easily available at supply houses.   The crucial
thing about poultices is the cleaning agent.  Alkaline-based for most
organic stains, acidic-based for rust and efflorescence (much trickier to
use without affecting the stone, especially calcareous), and solvent-based
for paint, graffitti, and similar stuff.

Solvents are indeed the best cleaning agent for silicones, but regular old
methylene chloride will not quite do the job.  Check out Prosoco's website
at http://www.prosoco.com/ProductList.asp?m=0&i=5 and scroll down the list
to Dicone NC9.  This is about the best cleaning agent I've found for
silicone stains, and there are no guarantees even then.  Also, check out
Fred Hueston's site regarding stain removal:
http://www.ntc-stone.com/tips.htm#removing%20stains  His site has many other
items of interest to stoneoids.

Good Luck!

Chas