Pouticing Candy And Confectionery Stains From Concrete

PREFACE: The cleaning or removal of stains from concrete may involve the use of liquids, detergents or solvents which may run off on adjacent material, discolor the concrete or drive the stains deeper into porous concrete. Use the products and techniques described here only for the combinations of dirt/stain and concrete specified.

PART 1–GENERAL

1.01 SUMMARY

1. This procedure includes guidance on removing candy stains from concrete by scrubbing with a detergent or by poulticing with a solvent.
2. 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.
   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.
3. See “General Project Guidelines” 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 Condition
      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).
4. For general information on poulticing, see 04455-02-R.

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. Detergent
2. For Stains Containing Chocolate:
   1. Ammonium Hydroxide (NH5O):
      1. A weakly basic compound that is formed when ammonia dissolves in water and that exists only in solution.
      2. Other chemical or common names include Ammonia water*; Aqua ammonia*; Household ammonia*.
      3. Potential hazards: TOXIC; MAY IRRITATE THE EYES.
      4. Available from chemical supply house, grocery store or pharmaceutical supply distributor, or hardware store.
   2. Denatured Alcohol:
      1. Other chemical or common names include Methylated spirit*.
      2. Potential hazards: TOXIC AND FLAMMABLE.
      3. Available from hardware store, paint store or printer’s supply distributor.
      4. Denatured alcohol, which carries no liquor tax, should be a satisfactory substitute for ethyl alcohol for stain removing purposes.
3. For Stains Resulting from Artificial Food Coloring:
   1. One of the following solvents:
      Carbon Disulfide (CS2):
      1. A colorless flammable poisonous liquid used as a solvent for rubber and as an insect fumigant.
      2. Other chemical or common names include Carbon bisulfide*; Carbon sulfide*.
      3. Potential Hazards: TOXIC AND FLAMMABLE.
      4. Available from chemical supply house, drugstore or pharmaceutical supply distributor, garden and lawn supply center, hardware store, or paint store.
         -OR-
   2. Carbon Tetrachloride (CCl4):
      1. A colorless, nonflammable, toxic liquid that has an odor resembling chloroform and is used as a solvent (as in dry cleaning) and a fire extinguisher.
      2. Other chemical or common names include Perchloromethane; Tetrachloromethane.
      3. Potential Hazards: TOXIC.
      4. Available from chemical supply house, dry cleaning distributor, hardware store, paint store or photographic supply distributor (not camera shop).
         -OR-
   3. Chloroform (CHCl3):
      1. A colorless volatile heavy toxic liquid with an ether odor used especially as a solvent or as a general anesthetic.
      2. Other chemical or common names include Methylene trichloride; Trichloromethane.
      3. Potential Hazards: TOXIC.
      4. Available from chemical supply house, dry cleaning supply distributor, drugstore or pharmaceutical supply distributor, or paint store.
   4. Filler material such as diatomaceous earth or talc
   5. Mineral water
   6. Clean dry towels for blotting the area after treatment
4. Accessible source of clean water, soap and towels for washing and rinsing in case of emergencies associated with the use of chemicals
5. Stiff bristle brushes (non-metallic)

2.02 EQUIPMENT

1. 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. Provide adequate wash solutions (i.e. water, soap and towels) before starting the job.
   2. Whenever acid is used, the surface should be thoroughly rinsed with water as soon as its action has been adequate. Otherwise it will continue etching the concrete even though the stain is gone.

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. Thoroughly saturate the surface with clean, clear water.
2. Using a stiff (non-metallic) bristle brush, try scrubbing the stained area with a detergent mixed with water.
3. Thoroughly rinse the surface with clean, clear water and allow to dry.
   -OR-
4. If this does not sufficiently remove the stain, try one of the following:
   1. For stains containing chocolate, scrub the surface with ammoniacal alcohol:
      1. Mix 1 part ammonium hydroxide solution (containing 26% ammonia) with 9 parts denatured alcohol.
      2. Thoroughly saturate the concrete with clean, ,clear water.
      3. Using a stiff bristle brush, scrub the solution over the stain.
      4. Thoroughly rinse the surface with clean, clear water and allow to dry.
      5. Repeat the process as necessary to achieve the desired level of cleanliness. —OR-
   2. If the stain is badly colored due to artificial food colorings, try poulticing with carbon disulfide, carbon tetrachloride or chloroform.
      1. Mix filler material and solvent to create a thick paste. Select the amount of filler to make a poultice of the required size. Add solvent to obtain the proper paste-like consistency.
      2. Thoroughly saturate the concrete with clean, clear water.
      3. Apply the poultice to the stained area using a wood or plastic spatula. Be sure to spread the poultice well beyond the stained area. The liquid portion of the paste will migrates into the concrete where it will dissolve some of the staining material. Then the liquid will gradually move back beyond the concrete surface and into the poultice, where it will evaporate, leaving the dissolved staining material in the poultice.
      4. When the poultice has dried, brush or scrape it off with a wooden scraper.
      5. Using a stiff bristle brush, scrub the surface with scouring powder and clean water to remove any residual staining.
      6. Thoroughly rinse the area with clean, clear\water and allow to dry.
      7. Repeat the process as necessary to achieve the desired level of cleanliness.