Spot Cleaning Oil Stains On Granite

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 THE POROUS STONE. USE THE PRODUCTS AND TECHNIQUES DESCRIBED HERE ONLY FOR THE COMBINATIONS OF DIRT/STAIN AND STONE SPECIFIED.

PART 1–GENERAL

1.01 SUMMARY

1. This procedure includes guidance on removing stubborn oil stains and discoloration in local areas from granite surfaces.
2. For guidance on spot cleaning other stains on granite, refer to the following:
   1. For iron stains: See 04465-01-R.
   2. For copper/bronze stains: See 04465-02-R.
3. Safety Precautions:
   1. DO NOT save unused portions of stain-removal materials.
   2. DO NOT store any chemicals in unmarked containers.
   3. EXCELLENT VENTILATION MUST BE PROVIDED WHEREVER ANY SOLVENT IS USED. USE RESPIRATORS WITH SOLVENT FILTERS.
      NOTE: SOME OF THE SOLVENTS LISTED ARE KNOWN CARCINOGENS AND MAY BE BANNED IN SOME STATES.
   4. No use of organic solvents indoors should be allowed without substantial air movement. Use only spark-proof fans near operations involving flammable liquids.
   5. Provide adequate clothing and protective gear where the chemicals are indicated to be dangerous.
   6. Have available antidote and accident treatment chemicals where noted.
4. 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).

5. For general information on the characteristics, uses and problems associated with granite, see 04465-01-S.

PART 2–PRODUCTS

2.01 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 (*).

1. For Scrubbing by Hand:
   1. Chemical Cleaning Compound: Hydrofluoric (HF) and phosphoric (H3PO4) acids in concentrations not exceeding 5% weight to volume, with surfactants such as ethoxylated alkylphenols and ethoxylated alcohols at concentration of 1 to 2% weight to volume. -OR-
   2. Cleaning Detergent: Cleaning detergent designed for use on masonry surfaces, free of deleterious amounts of acids, alkalies and organic materials, as recommended by manufacturer for masonry surfaces of work to be cleaned as acceptable.
2. Materials for Use on New Oil Stains (Paste Application):
   1. Benzol (C6H6):
      1. A colorless, volatile, flammable, toxic, liquid, aromatic hydrocarbon used in organic synthesis, as a solvent and as a motor fuel.
      2. Other chemical or common names include Benzene; Benzole; Phene; Phenyl hydride; Coal naphtha*; Motor benzol*.
      3. Potential Hazards: FLAMMABLE.
      4. Available from automotive supply distributor, chemical supply house, dry cleaning supply distributor, hardware store or paint store.
      5. Benzene and benzine should not be confused. Benzene is a distinct chemical compound obtained from coal tar. Benzine is a mixture of aromatic hydrocarbons of similar boiling points derived from petroleum.
   2. Hydrated lime or marble dust
3. Materials for Use on Linseed Oil Stains (Paste Application):
   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.
      1. Strong base-type powdered cleaning material sold under brand names.
      2. Other chemical or common names include Sodium Orthophosphate; Tribasic sodium phosphate; Trisodium orthophosphate; TSP*; Phosphate of soda*; (also sold under brand names such as).
      3. Potential Hazards: CORROSIVE TO FLESH.
      4. Available from chemical supply house, grocery store or supermarket or hardware store.
   2. Sodium Perborate:
      1. Other chemical or common names include Perborax*.
      2. Potential Hazards: TOXIC AND FLAMMABLE (WHEN IN CONTACT WITH ORGANIC SOLVENTS).
      3. Available from chemical supply house, drugstore or pharmaceutical supply distributor, grocery store or supermarket.
   3. Powdered talc
      -OR-
   4. Proprietary preparations of paste are also available and should be used according to their manufacturer’s published instructions.
4. Clean potable water

2.02 EQUIPMENT

1. For Poulticing:
   1. Glass or ceramic container for mixing the solution
   2. Wooden utensil for stirring the ingredients
2. Wood or plastic spatula
3. Stiff bristle brush (non-metallic)

PART 3–EXECUTION

3.01 PREPARATION

1. Protection:
   1. The use of wire brushes, steel wool, or abrasive tools for cleaning will not be permitted.
   2. Provide adequate wash solutions (i.e. water, soap and towels) before starting the job.

3.02 ERECTION, INSTALLATION, APPLICATION

NOTE: DO NOT TRY MORE THAN ONE TREATMENT ON A GIVEN AREA UNLESS THE CHEMICALS USED FROM PRIOR TREATMENT HAVE BEEN WASHED AWAY.

1. Using a Proprietary Cleaning Compound or Detergent:
   1. Apply chemical cleaner or detergent to stained surface following manufacturer’s instructions.
   2. Scrub the surface by hand using a stiff (non-metallic) bristle brush. Begin at the top of the stained area and work down.
   3. Thoroughly rinse the surface with clean, clear water and allow to dry.
   4. Repeat as necessary to achieve the desired level of cleanliness.
2. Poulticing New Oil Stains:
   1. Thoroughly rinse the area to be treated with clean, clear water.
   2. Mix a solution of benzol in a glass or ceramic bowl.
   3. Thoroughly moisten the stained area with this solution, being sure to dampen an area well beyond the stain.
   4. Mix the remaining liquid with hydrated lime or marble dust to form a paste the consistency of oatmeal or cake icing.
   5. Using a wooden or plastic spatula, apply the paste over the entire stained area in layers no more than 1/4 inch thick. Extend the poultice well beyond the stain to prevent forcing the stain into previously clean stone.
   6. Allow to dry (approximately 48 hours).
   7. After the poultice has set, dampen it with mineral water.
   8. Remove dried paste with wooden scrapers or spatulas.
   9. Thoroughly rinse the area with clean, clear water and allow to dry.
   10. Check for remaining residue and repeat the process if necessary to achieve the desired level of cleanliness.
3. Poulticing Linseed Oil Stains:
   1. Thoroughly rinse the area to be treated with clean, clear water.
   2. Make a paste composed of one part trisodium phosphate, one part sodium perborate and 3 parts powdered talc, mixed with a strong soap solution.
   3. Follow steps 3 to 10 in 3.02 B. above.

NOTE: Finished work shall show no signs of stains, scratches, streaks or runs of discoloration, mortar damage or other like defects from use of cleaners. Leave all masonry surfaces neat and clean.