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Historic Preservation - Technical Procedures

Spectitle:

Removing Pollution, Industrial, Petroleum-based, and Miscellaneous Stains From Limestone And Marble

Procedure code:

0440012R

Source:

Developed For Hspg (Nps - Sero)

Division:

Masonry

Section:

Stonework

Last Modified:

07/02/2012

Details:

Removing Pollution, Industrial, Petroleum-based, and Miscellaneous Stains From Limestone And Marble



REMOVING POLLUTION, INDUSTRIAL, PETROLEUM-BASED, AND MISCELLANEIOUS STAINS FROM LIMESTONE AND MARBLE


THE CLEANING OR REMOVAL OF STAINS FROM STONE MAY INVOLVE THE USE
OF LIQUIDS, DETERGENTS OR SOLVENTS WHICH MAY RUN OFF ON ADJACENT
MATERIAL, DISCOLOR THE STONE OR DRIVE THE STAINS DEEPER INTO POROUS
STONES.  USE THE PRODUCTS AND TECHNIQUES DESCRIBED HERE ONLY FOR
THE COMBINATIONS OF DIRT/STAIN AND STONE SPECIFIED.


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on the removal of
         industrial stains from limestone and marble by poulticing
         with a chemical solvent.  Industrial stains include smoke
         and soot, grease, oil, tar, asphalt, waxes, food stains,
         and handmarks.  

    B.   Industrial stains result from contact with such materials
         as fuel oil, asphalt and tar.  Industrial stains that
         have penetrated deeply into the masonry should not be
         rubbed in, but should always be removed with a poultice.

    C.   Some organic solvents that may be effective in removing
         industrial stains include:  naptha, mineral spirits,
         chlorinated hydrocarbons (such as methylene chloride and
         perchloroethylene), ethyl alcohol, acetone, ethyl
         acetate, amyl acetate, toluene, xylene, and
         trichlorethylene.

    D.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         These guidelines should be reviewed prior to performing
         this procedure and should be followed, when applicable,
         along with recommendations from the Regional Historic
         Preservation Officer (RHPO).

    E.   For general information on the characteristics, uses and
         problems associated with limestone, see 04460-01-S; for
         marble, see 04455-01-S.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.  The Procter & Gamble Co.
         www.pg.com
         
2.02 MATERIALS

    NOTE:  Chemical products are sometimes sold under a common
    name.  This usually means that the substance is not as pure as
    the same chemical sold under its chemical name.  The grade of
    purity of common name substances, however, is usually adequate
    for stain removal work, and these products should be purchased
    when available, as they tend to be less expensive.  Common
    names are indicated below by an asterisk (*).

    A.   For Surface Stains:

         1.   Non-sodium based bleach

              NOTE:  DO NOT USE BLEACH ON DARK COLORED STONES AS
              THIS WILL CAUSE THE STONE TO LIGHTEN.

         2.   Mineral Spirits:

              a.   A petroleum distillate that is used especially
                   as a paint or varnish thinner.

              b.   Other chemical or common names include
                   Benzine* (not Benzene); Naphtha*; Petroleum
                   spirits*; Solvent naphtha*.

              c.   Potential Hazards:  TOXIC AND FLAMMABLE.

              d.   Safety Precautions:

                   1)   AVOID REPEATED OR PROLONGED SKIN CONTACT.

                   2)   ALWAYS wear rubber gloves when handling
                        mineral spirits.

                   3)   If any chemical is splashed onto the
                        skin, wash immediately with soap and
                        water.

              e.   Available from construction specialties
                   distributor, hardware store, paint store, or
                   printer's supply distributor.

    B.   For Smoke and Soot:

         1.   Methyl Chloroform:

              a.   Other chemical or common names include 1,1,1-trichloromethane.

              b.   Potential Hazards:  TOXIC.

                   IMPORTANT:  Methyl chloroform is often known
                   as 1,1,1-trichloromethane.  It has similar
                   solvent properties to trichlorethylene and
                   carbon tetrachloride whose usage is not
                   recommended on safety grounds.  Care must be
                   taken with methyl chloroform although it is
                   much less hazardous than the other chemical
                   solvents mentioned.  Ensure good ventilation
                   and/or respiratory apparatus.

              c.   Available from chemical supply house.

              -OR-

              Trisodium Phosphate (see Section 2.02 C.1. below)

    C.   For Grease, Oil, Foodstains or Handmarks:

         1.   Trisodium Phosphate:

              NOTE:  THIS CHEMICAL IS BANNED IN SOME STATES SUCH
              AS CALIFORNIA.  REGULATORY INFORMATION AS WELL AS
              ALTERNATIVE OR EQUIVALENT CHEMICALS MAY BE
              REQUESTED FROM THE ENVIRONMENTAL PROTECTION AGENCY
              (EPA) REGIONAL OFFICE AND/OR THE STATE OFFICE OF
              ENVIRONMENTAL QUALITY.

              a.   Strong base-type powdered cleaning material
                   sold under brand names.

              b.   Other chemical or common names include Sodium
                   Orthophosphate; Tribasic sodium phosphate;
                   Trisodium orthophosphate; TSP*; Phosphate of
                   soda*; (also sold under brand names such as).

              c.   Potential Hazards:  CORROSIVE TO FLESH.

              d.   Available from chemical supply house, grocery
                   store or supermarket or hardware store.

         -AND-

         2.   Sodium Perborate:

              a.   Other chemical or common names include
                   Perborax*.

              b.   Potential Hazards:  TOXIC AND FLAMMABLE (WHEN
                   IN CONTACT WITH ORGANIC SOLVENTS).

              c.   Available from chemical supply house,
                   drugstore or pharmaceutical supply
                   distributor, grocery store or supermarket.

         -OR-

         3.   Acetone (C3H6O):

              a.   A volatile fragrant flammable liquid ketone
                   used chiefly as a solvent and in organic
                   synthesis and found abnormally in urine.

              b.   Other chemical or common names include
                   Dimethyl ketone; Propanone

              c.   Potential Hazards:  VOLATILE AND FLAMMABLE
                   SOLVENT

              d.   Available from chemical supply house or
                   hardware store.

         -AND-

         4.   Amyl Acetate:

              a.   Other chemical or common names include Amyl
                   acetic ester; 1-pentanol acetate; Banana oil*;
                   Pear oil*.

              b.   Potential Hazards:  FLAMMABLE.

              c.   Available from chemical supply house,
                   drugstore or pharmaceutical supply
                   distributor, paint store or photographic
                   supply distributor (not camera shop).

    D.   Suitable filler such as talc, chalk, clay, cotton pads,
         or cotton flannel.

    E.   Neutral pH liquid soap such as "Joy" (Procter & Gamble),
         or approved equal.

    F.   Clean, potable water

2.03 EQUIPMENT

    A.   Garden hose and pneumatic spray nozzle

    B.   Stiff bristle brushes (no iron wire)

    C.   Wood scrapers, knife blades and spatulas


PART 3---EXECUTION

3.01 ERECTION/INSTALLATION/APPLICATION

    A.   Removing Surface Stains:

         1.   Superficial (or surface) stains may be removed by
              gently scrubbing with a scouring powder containing
              bleach (none which are sodium-based) or water-based
              household detergents that are acid and alkali-free.

              NOTE:  The use of bleach may depend on the color
              and type of stone.

         2.   Brush with an emulsion of mineral spirits and rinse
              with clean, clear water.

         3.   Allow to dry.

    B.   Removing Smoke and Soot:

         1.   Scrub stained area with a neutral pH liquid soap.

         2.   More stubborn patches may be pulled from the
              masonry pores using a poultice based on methyl
              chloroform; Another useful poultice contains
              trisodium phosphate and bleaching powder.
              For guidance on poulticing, see 04455-02-R.

    C.   Removing Grease, Oil, Food Stains or Handmarks:

         1.   Thoroughly scrub the surface with soap, non-abrasive
               scouring powder and trisodium phosphate to
              remove excess debris.

         2.   Apply a poultice of 1 part trisodium phosphate, 1
              part sodium perborate, and 3 parts talc in a hot
              neutral pH detergent solution in water.  A useful
              proprietary de-greasing caustic alkali cleaner is
              available to break down greasy surface soiling,
              particularly on surfaces exposed to pollution from
              vehicles, and may be successfully used as a
              preliminary preparation for cleaning by other
              methods.  Thorough removal from the surface is
              essential.  For guidance on poulticing, see 04455-02-R.

         -OR-

         1.   Mix 1 part acetone and 1 part amyl acetate.

         2.   Soak a non-dyed cotton flannel in the solution and
              place the flannel over the stain (clay may also be
              used to form a pack).

         3.   Keep the flannel or the clay on the stain for three
              days under a thin film of plastic.

         4.   Remove poultice with wooden spatulas or scrappers,
              and thoroughly flush surface with mineral water.

                         END OF SECTION
 


industrial stains, pollution, petroleum, smoke, soot, grease, oil, tar, asphalt, wax, food stains, handmarks, limestone, marble