StonePly and Stains
StonePly stone panels are made from natural marbles, granites, and limestones. All natural stones are porous by nature and easily absorb stains. However, removing stains can be easy by using a material to absorb the stain from the stone called poultice. It is important to identify the type of stain so that the proper type of poultice mixture is used.
What is a Poultice?
A poultice is a white absorbent powder mixed with a chemical to help aid in the removal of a stain by absorbing the stain from the stone surface. The poultice powder materials can be found at most hardware stores and include: white molding plaster, talc, white chalk, and clays. Also, in place of the white powder, an absorbent material such as white paper towels, white gauze pads, and white cotton balls can be used.
If using a powder poultice, the poultice should be mixed with the appropriate chemical to form a thick paste. If using an absorbent material poultice other than powder, the material should be soaked in the chemical and then rung out so it is moist, but not dripping.
Spread the poultice over the stained area using a wooden or plastic spatula. The poultice should be 1/4" to 1/2" thick. The poultice should be covered and sealed with plastic for 24 to 48 hours until the poultice is dry. To aid in the drying process, holes can be poked in the plastic. Once the poultice is dry, it should be removed with the wooden or plastic spatula and then rinse the spot thoroughly. For stubborn stains, repeat this process several times as necessary. Any "whitening" chemicals used such as bleach, ammonia, or hydrogen peroxide should be diluted with water. Re-polishing may be necessary on some stones.
Common Types of Stains:
- Biological (fungus, mildew)
- Efflorescence
- Ink (pen, magic marker)
- Metal (rust, iron, copper, bronze)
- Oils (grease, cooking oil, tar, cosmetics)
- Organic (food, coffee, tea, tobacco)
Removing Stains
Biological Stains
Most biological Stains can be easily removed without the use of poultice by using a water/bleach, water/ammonia or water/hydrogen peroxide combination. Dilute 1/2 cup of the chemical in one gallon of water. Clean area thoroughly. If the stain still remains then a poultice can be made with a white powder and one of the diluted chemicals listed above.
Efflorescence
Efflorescence is mineral salts found in stone that are brought to the surface when water in the stone evaporates. It looks like a white powdery substance on the surface of the stone. Normally this is a temporary problem and the white powder can be wiped away from the surface. Once the stone dries out, efflorescence should not be a problem. For more information, visit our technical bulletin on efflorescence.
Ink Stains
Pen and marker stains are extremely hard to remove from the surface of natural stone. For dark stones, acetone can be used to clean the surface of the stone where the stain appears. A water/bleach mixture can be used for light colored stones, but caution should be used. For a less direct approach, a poultice can be used by combining the white powder with the appropriate chemical above.
Metal Stains
Iron or rust metal stains are the most common metal stains found on stone and possibly one of the hardest stains to remove. It may take several poultice mixtures to successfully remove all of the metal stain. A poultice mixed with white powder and any rust remover chemical should be applied to the stain. Copper stains can be just as difficult to remove as iron stains. A poultice mixed with white powder and diluted ammonia should be used. It may take several tries before you notice any results.
Oil Stains
Before trying a poultice mixture, clean the surface with diluted ammonia or mineral spirits. If this does not remove the stain, you can try to clean the surface with acetone (for dark stones) or diluted bleach (for light stones). If both of these methods do not yield results, then a poultice made of white powder mixed with mineral spirits can be used.
Organic Stains
Organic stains can be removed by using a powder poultice mixed with acetone or diluted hydrogen peroxide. Acetone should be used only on darker stones and hydrogen peroxide only on lighter stones.
This technical bulletin is provided by StonePly. It is intended for guidance only.
Copyright 2007, StonePly Inc. All rights reserved.
