Proper stone maintenance practices that are performed daily will help prevent staining problems. The best two methods of stain prevention are to treat the stone with Stone Savior Sealer and to immediately pick up spills before they are absorbed into the stone.
The objective of a penetrating sealer is to prevent liquids from absorbing through the stone surface. However, if a spill sets for a long period of time the stone may absorb the liquid even with a sealer. Natural stone is porous by nature. Stone stains very easily because its pores will absorb the liquid like a sponge. The older a stain gets, the more difficult it is to remove.
One question that is often asked is how are stains removed from stone? The only safe way to remove a stain is to reabsorb it out of the stone. Since the stain was absorbed through the pores, it must be reabsorbed through the pores. The natural absorption process must be reversed.
In order for a stain to be removed, the type of stain must be identified. Different types of stains have various removal processes. There are five common types of stains:
- Organic: Coffee, tea, food, cosmetics, and plant food
- Biological: Mold, mildew, algae, and fungus
- Metal: Rust, iron, bronze, copper, etc.
- Ink: Pen and magic marker
- Oil Based: Tar, grease, cooking oil, skin and hair oil
To determine the type of stain you must ask the correct questions and be aware of the following:
What is the color and pattern of the stain?
What sat near the stain previously?
Are there plumbing pipes or air ducts near the stain?
Was there a plant near the stain?
Is the stain associated with a certain location?
How old is the stain?
Once the stain is determined, an appropriate stain removal method must be utilized. Knowing the absorption level and chemical sensitivity of the stone will help determine the method to be used. If the stain cannot be identified, then a test patch with different methods should be used. The process that works the best should be used for the area affected.
The first step try using a commercial cleaning product or household chemical
Types of Stains And Removal Procedures
Oil-based stains (grease, tar, cooking oil, cosmetics). An oil-based stain will darken the stone and normally must be chemically dissolved so the source of the stain can be flushed or rinsed away. Remove excess staining agent by wiping or chipping (iftar) first. Clean gently with a soft liquid cleanser, household detergent, ammonia, mineral spirits, or acetone. Do not pour the cleaner directly on the staining agent – this can result in thinning the contaminant and furthering its spread. Partially saturate a paper or cloth towel with the cleaner and attempt to draw the stain into the towel.
Organic stains (coffee, tea, fruit, tobacco, paper, food, urine, leaves, bark, bird droppings) may cause a pinkish-brown stain and may disappear after the source of the stain has been removed. Outdoors, with the sources removed, normal sun and rain action will generally bleach out the stains. Indoors, clean with 12% hydrogen peroxide and a few drops of ammonia.
Inorganic metal stains (iron, rust, copper, bronze). Iron or rust stains are orange to brown in color and leave the shape of the staining object, such as nails, bolts, screws, cans, flowerpots, or metal furniture. Copper and bronze stains appear as green or muddy brown and result from the action of moisture on nearby or embedded bronze, copper, or brass items. Metal stains must be removed with a poultice (see Section 9.0 of this chapter on Poultices). Deep-seated, rusty stains are extremely difficult to remove, and the stone may be permanently stained.
Biological stains (algae, mildew, lichens, moss, fungi). Clean with dilute (ó cup in a gallon of water) ammonia, bleach, or hydrogen peroxide. WARNING: DO NOT MIX BLEACH AND AMMONIA! THIS COMBINATION CREATES A TOXIC GAS!
Ink Stains (magic marker, pen, ink). Clean light-colored stones with bleach or hydrogen peroxide. Use lacquer thinner or acetone for dark-colored stones. Do not pour the cleaner directly on the staining agent – this can result in thinning the contaminant and furthering its spread.
- Partially saturate a paper or cloth towel with the cleaner and attempt to draw the stain into the towel.
Paint Stains. Small amounts can be removed with lacquer thinner or scraped off carefully with a razor blade. Heavy paint coverage should be removed with a commercial liquid paint stripper. DO NOT USE ACIDS OR FLAME TOOLS TO STRIP PAINT FROM STONE.
Water spots and rings (surface accumulation of hard water). Buff with dry 0000 steel wool.
Fire and Smoke Damage. Older stones and smoke- or fire-stained fireplaces may require a thorough cleaning to restore their original appearance.
Etch Marks. Caused by acids left on the surface of the stone, some will etch the finish but not leave a stain; others will both etch and stain. Once the stain has been removed, wet the surface with clear water and sprinkle with marble polishing powder. Rub the powder into the stone with a damp cloth or by using a buffing pad with a low-speed power drill or polisher. Continue buffing until the etch mark disappears and the marble surface shines. Honing may be required for deep etching. This process may require the services of a Professional Refinisher.
Efflorescence. A white powder that may appear on the surface of the stone, it is caused by water carrying mineral salts from below the surface of the stone to the surface and evaporating. When the water evaporates, it leaves the powdery salt residue. If the installation is new, dust mop or vacuums the powder. Repeat as necessary as the stone dries out. Do not use water to remove the powder. If the problem persists, contact a Contractor to identify and remove the cause of the moisture.
If this process did not work to remove the stain, an absorbing poultice must be used. A poulticing material can be anything that absorbs from a cotton ball to a paper towel or even a cotton shirt. In most cases, an absorbing powder poultice is used to extract a stain.
In the poulticing process, the stone will absorb the chemical from the poultice, then the chemical loosens the stain, and the poultice reabsorbs the stain from the stone. During this process, it is important, to begin with, the gentlest method first.
Second try and remove the stain with Stone Savior Poultice Powder mixed with Countertop cleaner. If the stain still remains, then begin the poulticing process.
Poultice Mixtures For Various Stains
- Oil-Based Stains. Poultice with baking soda and water or one of the powdered poultice materials and mineral spirits or a commercial degreaser.
- Organic Stains. Poultice with one of the powdered poultice materials and 12% hydrogen peroxide solution, or use acetone instead of hydrogen peroxide.
- Iron Stains. Poultice with diatomaceous earth and a commercially available rust remover. Rust stains are particularly difficult to remove; professional assistance may be required. Many rust removers contain acids that will etch marble, limestone, and certain granites.
- Copper Stains. Poultice with one of the powdered poultice materials and ammonia. These stains are difficult to remove; professional assistance may be required.
- Paint Stains (Water-based). Poultice with one of the powdered poultice materials and a commercial paint remover.
- Paint Stains (Oil-based). Poultice with one of the powdered poultice materials and mineral spirits. Deep stains may require methylene chloride. When using highly volatile solvents in poulticing, use a paper towel, pouring the solvent on the paper towel and then placing the towel on the stained area.
- Ink Stains. Poultice with one of the powdered poultice materials and mineral spirits or methylene chloride. When using highly volatile solvents in poulticing, use a paper towel, pouring the solvent on the paper towel and then placing the towel on the stained area.
- Biological Stains. Poultice with one of the poultice materials and dilute ammonia or bleach or hydrogen peroxide. WARNING: DO NOT MIX AMMONIA AND BLEACH! THIS COMBINATION CREATES A TOXIC GAS!
- Flammable Materials. The preceding text does not purport to address possible safety concerns associated with the use of flammable solvents. The user is directed to the manufacturer’s labeling and MSDS for further direction in the safe handling and use of these products.
Applying The Poultice
- Wet the stained area with distilled water. This will isolate and intensify the removal process. (Do not use hot water and do not apply if the air temperature is below 32 degrees).
- If a powder is used, blend the powder and the chemical or water to a thick paste consistency like peanut butter. See stain identifier for the chemical to be added to the powder. Once you have mixed the ingredients apply with a wood spatula.
- Apply a layer of about ¼” thick to the affected area.
Do not place the paste on to any unaffected area
- Cover the poultice with plastic food wrap and tape down the edges with an easy to remove adhesive. This traps the moisture and prevents the poultice from drying too quickly.
- BE sure the poultice is completely dry before removing the wrap. Proper drying time is 24-48 hours. If the poultice is removed early, the stain may not be removed.
- When dry, take the wrap off and remove the dry poultice with a wooden spatula. The poultice should now be hard. Rinse the area with Stone Savior Countertop cleaner and wipe off with a clean terry cloth towel.
- If the stain reappears, repeat the process again. It may take a few applications for complete removal, especially for older stains and polished stone (Polished stone has smaller pores, therefore, stain removal may require an extra application).
- Dispose of used poultice in proper container.
- Use Stone Savior Sealer and reseal the affected area
Always wear safety goggles and gloves when mixing chemicals together
Mix chemicals in a well-ventilated area
If stains are very large in size or are serious, consult with a representative of Stone Savior
Do not reapply used poultice powders
Never mix more than one chemical together in the same poultice