>We have some marble in our lobby floor and steps, and are wondering on the
>best way to clean and polish it. (etc...)

A similar question was posed back in the fall of '95.  I saved the
responses, which I have posted below.
I hope they help.

HBC

Original Query (Fall 1995)
>Does anyone have a formula that meets conservation approval to clean
old yellowed marble from the 1890's that has been neglected.Years of
dirt to remove and yards of marble to clean in an old soda fountain
/drugstore counter tops.  Of course the design department needs it
yesterday!!  Perhaps someone has their grandma's old time household formula book
like Spon's Household Formulae.  I've tried Triton X-1009negligable
results),mild solution of ammonia (removes some dirt). It was suggested to
wet sand with 600 paper in
combination with Triton x 100 .This worked well on my sample but felt I
was being rather too intrusive!

Poultices would take too long.I am aware marble cutters have commercial
products but will nopt devulge the formulae.
Your suggestions within the relm of conservation ethics would be very
welcomed!

Regards
Len Hambleton-Objects Conservator
North Carolina Museum of [log in to unmask]

Answers/Replies

(1)
Len, I have always found marble to be such a porous material that removing
deeply imbedded stains is almost impossible. The greatest success I had
in cleaning the surface used a mixture of acetone and denatured alcohol,
applied with 0000 steel wool, and wiped with water as a final rinse.
For bleaching, I had moderate success on Carrara marble using oxlic acid
mixed with whiting (something with a calcium carbonate base) and applied
overnight as a poltice.  Please do not sand, you will never restore the
appearance of the original polish, and you will open the marble for
further staining in the future.  Clean the surface of accumulated dirt, and
accept the results as an honest representation of aged marble.
Gary M. Turnquist

conservator
Appalachian Cultural Museum
Boone, N>C>


(2)
Len,
A useful source for information about the make-up of proprietary formulae
is the book, <Clinical Toxicology of Commercial Products>.  It is updated
regularly.

There is also a listing in the book of generic compounds.

In my copy there are two generic recipes for cleaning marble:

Abrasive:                  88%
Sodium tripolyphosphate     5%
Alkyl aryl sodium sulfonate 5%
Trisodium phosphate         2%


Stoddard solvent           0-31%
Morpholine                 0-2%
Trisodium phosphate        0-3%
Soap                       0-3%
Wetting agent              0-1%
Silica                     0-65%
Water                      to 100%


Hope this helps.

Jack C. Thompson
Thompson Conservation Lab
Portland, OR

[log in to unmask]

(3)
Len:
I used a thick paste of baking soda and water to clean yellowing from a
white marble end table with good results.  If all else fails, try spraying
with plain bleach.
>Lynn Murdoch

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