Smoke Stain

Some smoke stains cannot be removed. If exposed to high temperature, as in fire, there is nothing that removes it. Sandblasting does not remove the stain, just the face of the brick. Smoke stains on the face of a fireplace as a result of lighting a fire with the damper closed can be removed easily. A commercial cleaning agent obtainable from a chemical company works very well. Mix solution according to manufacturer’s instructions, and cover carpet and surrounding areas that may be splattered during cleaning.

Using a hand-held brush, commence scrubbing at the top. After scrubbing the face with the cleaner, rinse the brush and scrub with clear water. Dip a cloth in clear water and wipe before it dries. Do not use terry cloth toweling or other material that leaves lint on bricks. Safety goggles and rubber gloves must be worn, as these chemicals are very caustic and case burns to skin.

To remove smoke stains from marble fireplaces, try a solution of detergent and water. If some stains fail to respond, wipe with cloth soaked with peroxide, and tape it over the stain. Place vis-queen over the cloth to prevent evaporation of peroxide. A second choice is to mix ½ cup of TSP (monobasic sodium phosphate) to 1 gallon of water and, following cleaning procedure outlined above, to remove light smoke stains. A third choice is a mixture of water and kitchen detergent. Do not attempt to remove smoke stains with muriatic acid as it will not remove them. (Muriatic acid more commonly known as Hydrochloric acid is a mixture of hydrogen chloride and water. It is widely used for treating iron and steel as a form of rust prevention).

If satisfactory results are not obtained from the aforementioned procedures, commercial marble cleaners and polishing products are available. Oil-base polish or soft waxes like bees-was should not be applied; they may cause discoloration of the marble.

Paint Stains
Apply commercial gel paint remover with paintbrush and work gel into paint stain. On brick or similar porous surfaces, rapid absorption of liquid removers prevents any action on stains. Gel removers remain on the surface and emulsify stains. Remove gel with either hot or cold-water pressure before it dries.

The same basic procedures remove spray paints, crayons, and graffiti from brick masonry and stucco. Water neutralizes paint removers, therefore allow surface to dry between each application. On heavy stains, more than one application may be necessary. Read and follow the manufacture’s instructions for proper use of products.

If the paint has penetrated the surface, as on bricks, the paint remover gel and most paint removers do not draw the paint to the surface. Therefore, they remove the paint from the surface only.

Paper Stains
Visqueen and paper are the most commonly used materials to wrap brick for shipment. Visqueen does not create any problems. But once the paper becomes wet, it causes stains on the brick. The metal bands used to secure the bricks to the pallets also leave stains. However, once the bricks are in the wall, hot water pressure and muriatic acid solution does remove the stains.

Electrical Lubricant
The yellow lubricant electricians use when pulling wires through conduit creates a stubborn stain to remove from brick walls. It is a gel type substance and hot water pressure alone does not remove it. Apply commercial gel paint remover to emulsify it. Once emulsified, it can be removed with hot water pressure or scrub brush.

Tire Marks
Tire marks on brick and concrete walls from equipment having run the tire along on the wall cannot be removed with hot water and acid. A gel paint remover applied to the stain with a paintbrush, then flushed with hot water pressure or use of a scrub brush usually removes it. If the tire marks are unusually heavy, use a blowtorch and finish with a gel paint remover. If one or more applications are necessary make certain the surface is dry before the second application is applied, as water neutralizes the gel. Rinse with hot water and pressure, if available. If not, scrub with a stiff fiber brush and flush with a garden hose to remove the residue.

Rust Stains
To remove rust from concrete, use a paste or mix one pound of oxalic acid crystals to one gallon of water. Pre-soak with water, apply solution, scrub with stiff fiber brush and rinse with clear water. Rinsing, when required, should be done before surface becomes dry.

Several applications of cleaning agent may be required on tough stains. Rust remover jelly used on metal may be used also. If manufacturer’s instructions for rust removal do not remove stains, experimentation will be necessary. One other alternative is to mix seven parts lime-free glycerin liquid with a solution of one-part sodium citrate granules in six parts hot water. Mix with powdered whiting to form a paste (see poultices).

Poultices
The use of poultices for removal of stains is more of a "hit and miss" proposition than using chemical cleaning solutions. The type of stain must be known for successful removal of stains with either method. The correct cleaning agent to successfully remove the stain must also be determined. A stronger mixture can be applied if the cleaning agent does not cause further damage to the surface, or immediate area surrounding the stain. Use caution if the possibility exists that the cleaning agent may cause further damage. A too-strong mixture could cause more problems than what originally existed.

There may be chemical agents available that may remove some of the stains noted in this section, but they may not always be available in the area where the job is located. On these occasions, knowing how to mix and apply a poultice will be beneficial. A poultice involves the mixing of various ingredients together to form a paste. The components consist of a cleaning agent or agents, water and a bonding agent. No water is added if the cleaning agent is a solvent. The cleaning agent is either a liquid, a powder or in crystal form.

The bonding agent must be an inert material such as whiting, bentonite clay, or other similar material (a pure-white chalk (calcium carbonate) that has been ground and washed). Regardless of the type of stain, the method for applying poultices remains the same. To mix: dissolve the powder or crystal ingredients in hot water, if available, as they dissolve more quickly and completely. After the powder or crystals are completely dissolved, add the bonding agent. However, do not add or mix the bonding agent until preparation of the stained area is complete. Scrape, sand, and wet it down with water. Be certain before spraying it with water that the water will not neutralize the cleaning agent in the mixture. Do not apply water to a petroleum base stain, nor one that is to be applied with a poultice containing solvent as the cleaning agent.

After the aforementioned procedures have been completed, and the type of stain has been determined, mix the cleaning agent with the bonding agent to form a paste. Using a putty knife or a trowel, apply a layer of paste at least one-quarter (1/4) inch thick onto the stain. Cover the area with vis-queen to contain the moisture and to protect the paste from moisture that may remove it. Leave the poultice in place from twelve (12) to twenty-four (24) hours or until it dries. The time of year and the temperature of the surface being cleaned are the determining factors on how quickly the poultice dries. Remove the vis-queen, flush off the residue and reapply the poultice if the stain has not been satisfactorily removed.

The mixture proportions listed herein may not successfully remove the stains in all instances. The variables involved do not permit a consistent formula that would be applicable in all situations. The type of surface, weather conditions, the age, type, quantity, and location of stain, interior or exterior, are some of the conditions to consider when evaluation stain removal.

If the mixture was of sufficient strength and failed to remove the stain, the probability of removal with more than two applications of the poultice is not encouraging. A stronger mixture or a different cleaning agent may be required. Using an incorrect cleaning agent may set the stain and make removal very difficult or impossible.

If the cleaning contractor bids the removal by the job, he bears any additional cost for satisfactory removal – unless unusual circumstances, not of his making, prevent the removal. Only then should an attempt to negotiate a new contract be considered. If bid by the hour, at forty ($40) to ($50) dollars, have additional expenses approved by the person with authority before proceeding. There is a cutoff point when the contractor or owner may decide the expenses out weight the importance of having the stain removed completely.

Remember, more than one treatment may be required to accomplish adequate removal. The poultice may remain on the stain twenty-four (24) hours or more before it dries. On surfaces such as brick, concrete block, or other concrete it is not practical to expect removal of all evidence of a stain over having existed.

Copper or Bronze Stains
Oxidation of copper pipes or fittings, or bronze plagues, creates either green or brown stains. If a poultice containing one part ammonium chloride salts, one part household ammonia water, and four parts powdered whiting does not remove the stain; wash it with a solution of oxalic acid salts in a gallon of water, after removing the poultice. Scrub with a stiff bristled fiber brush until maximum results have been obtained.

Stains on which poultices are applied are normally insufficient in size to warrant bidding by the square foot. However, until proficiency is obtained in the use of poultices, it is better to bid by the hour rather than by the job. The procedure applies to the removal of any stains whenever poultices are used.

Iron Stains
Oxalic acid is probably the oldest bleaching agent around. Being a bleaching agent it may bleach the area surrounding the stain along with the stain itself. So exercise caution when using this solution to bleach stains, especially when using a strong solution. There are several options available for removal of iron stains from masonry surfaces. One is a mixture of one pound of oxalic acid crystals dissolved in one gallon of water, mixed with one pound of whiting or some other bonding agent to form a paste. The addition of one-half pound of ammonium bifloride powder dissolved with the oxalic acid then mixed with the bonding agent to form a paste increases the reaction.

Ammonium bifluoride, (A rhombohedral or flaky crystal that can deliquesce easily and dissolve easily in water. It can dissolve in alcohol slightly. It can be resolved when affected by the heat or it is in hot water. It can corrode glass and it is poisonous), generates hydrofluoric acid and etches brick or concrete. It may create a bigger problem then the stain, so precaution is necessary when using it as a cleaning agent. A third option is hot water pressure and a muriatic acid (hydrochloric acid) solution. Always wear rubber gloves, goggles and protective footwear when using these solutions.

One other option is to combine seven parts lime-free glycerin liquid with a solution of one-part sodium citrate granules in six parts lukewarm water and mix with whiting to form a thick paste. Apply a layer of paste at least one-quarter inch thick over the stain with a putty knife or a trowel. Protect it from moisture by covering it with visqueen and leave in place twelve to twenty-four hours or until dry. Remove visqueen and flush area thoroughly with water. More than one application may be required to remove stains. Always flush the area thoroughly with clear water. A poultice solution of sodium hydrosulphate salts with an inert powder (such as whiting) also removes iron rust stains.

Oil Stains
Dissolve one pound powdered trisodiumphosphate (TSP) in one gallon of water; add whiting to form a paste. Using a putty knife or a trowel, apply a minimum one-quarter inch layer of past to the oil stain. Cover the stain with visqueen and leave in place twelve to twenty-four hours or until dry. Remove visqueen and rinse wall thoroughly. To remove oil stains from concrete, wipe excess oil from surface and saturate spots with paint thinner. Immediately cover with an absorbent such as cement, dry sand, baking soda, whiting or cat litter. Leave overnight and sweep the next day, if necessary repeat application. If there is darkening of concrete, apply a solution of liquid laundry bleach.

Welding Splatters
The owner or contractor may decide not to attempt removal of welding and metal splatters. Additional damage may occur during removal process and surface would have to be replaced. The splatters melt and adhere to the surface becoming an appendage. As the surface is already damaged, it may not be advantageous to risk further damage by attempting to remove the splatters. But if the contractor or person in authority determines the consequence is worth the gamble, use the following procedure.

Using a putty knife, scrape as much off as possible without causing more damage. After the initial scraping, alternate scraping with sandpapering the splatters with coarse sandpaper. If the texture of the surface is smooth, as smooth face brick, or concrete, use precaution when using these cleaning agents. Ammonium bifloride generates hydrofluoric acid, which etches masonry surfaces.

After removing as much of the splatters with scraping and sandpapering as possible, dissolve one-half pound of powdered ammonium bifluride and one pound of oxalic acid crystals in one gallon of water. Mix the solution with whiting to form a paste, and apply a layer of paste at least one-quarter inch thick over the stain. Protect the poultice from moisture with visqueen and leave in place for twelve to twenty-four hours or until dry. Remove visqueen and flush the area thoroughly with water. More than one application may be required for sufficient removal. Wear rubber gloves, goggles, and protective footwear when using caustic material. Flush any paste or solution from bare skin immediately.