Natural stone is a popular material used in many applications such as flooring, countertops, and monuments. However, most natural stones are porous and if not protected, can become stained. Stains can make stone look unsightly and can sometimes be challenging to remove. Fortunately, there is an effective way to remove most stains from hard porous surfaces.

Stains on natural stone and other hard porous surfaces can be effectively removed by using a poultice. A poultice is a paste-like mixture that is applied to the surface of the stain to break down the stain and draw it out of the stone. A poultice is made by mixing a dry/powdered material with a liquid cleaning agent to form a thick paste. Common powdered materials used in making poultice include baking soda, talc, chalk, and diatomaceous earth. The cleaning agent is determined by the type of stain.

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Refer to our STAIN MANAGEMENT APP for a list of the types of stains and the chemicals to use to break down the stain, and a how-to video.

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The first step in removing a stain from stone using a poultice is to identify the type of stain. This is important because the type of stain will determine the type of poultice to use. For example, oil-based stains require a different poultice than water-based stains. Once you have identified the type of stain, you can proceed with making the poultice.

To make the poultice, mix the powdered material with the liquid until you get a thick paste. The consistency of the paste should be similar to peanut butter. The amount of powder and liquid to use depends on the size of the stain. For small stains, you will need a small amount of poultice, while larger stains will require more poultice.

Apply the poultice to the stain and cover it with plastic wrap or a plastic bag. This will help to keep the poultice moist and prevent it from drying out. Leave the poultice on the stain for 24 to 48 hours. The longer you leave the poultice on the stain, the more effective it will be at drawing out the stain from the stone.

After 24 to 48 hours, remove the plastic wrap or bag and scrape off the poultice with a plastic spatula. Rinse the area with clean water and dry it with a clean cloth. You may need to repeat the process several times to completely remove the stain from the stone.

• For most organic stains use peroxide as the liquid. But not the peroxide you find at the drug store. You will want to use the same strength of peroxide that you can find at beauty supply stores (sold as developer for hair coloring).
• For ink you will need to use a solvent such as acetone or mineral spirits.
• For rust you can use a commercial iron remover such as Iron Out.

Removing stains from stone using a poultice is an effective and easy way to restore the appearance of stone surfaces. The key to success is identifying the type of stain and using the right poultice. With a little patience and persistence, you can remove even many of the toughest stains. Remember though, a properly sealed surface will be protected from staining, so make sure your stone is properly sealed. Call us if you have any questions.

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By Fred Hueston. This article is one of a series of articles written and published on behalf of Surface Care PROS Partners.