How To Clean Blood from Granite, Marble & Stone
Blood stains can result from injuries or from food preparation. Blood stains should be treated as soon as possible because they can set quickly. Where water is called for, use cold water rather than warm to avoid setting the blood stain. If you are concerned about hard water marks on marble, use distilled water.
The minerals in natural stone vary and so that means the surfaces vary both in their reaction to stains and to methods for stain removal. Marble and granite are the two most common choices for the home and the following solutions are suitable for their care, unless otherwise noted. The solutions here are designed to be as universal as possible, but may contain pointers for different compositions and colors of stone.
Before moving on to the most difficult, soaked in stains, it's worth noting that a well-sealed natural stone countertop is likely to be extremely resistant to stains, even ones as deeply pigmented as blood. Although natural stone is itself porous, the sealants are often applied after installation and are recommended to be re-applied regularly to help maintain the stain resistance of the surface. For a natural stone surface that is well sealed, contain, soak up and remove the stain with clean dry paper towels. If the surface is particularly glossy, you may wish to use soft cloths rather than paper towels to help preserve the finish. Use a blotting, rather than wiping motion. Apply a small amount of neutral pH soap like Dove to a clean, soft sponge wet with water. Sponge the affected area to remove remaining blood residue. Once the entire area has been cleaned, remove the soap residue with a clean soft sponge, free of soap, wet with water. Use a squeegee to wick away extra moisture and avoid over-wetting and pooling that may damage your countertop and encourage build-up.
A natural stone surface where the sealant as worn off or is otherwise absent may require more aggressive treatment to address soaked-in stains. As with a well-sealed surface, first contain, soak up and remove blood pooled on the surface with clean dry paper towels or soft cloths using a blotting rather than wiping motion. Apply a poultice made with a talc base and dilute ammonia (5%) liquid cleaning agent. As an alternative for lighter stones, you can make a poultice made with equal parts flour and powdered borax as a base and hydrogen peroxide as the liquid cleaning agent. For darker stones you may wish to use powdered dish detergent and distilled water. In general acidic remedies should be avoided for calcareous stone like marble, and caution should be used when treating colored stones.
Place between 1/4 cup and 1/2 cup of poultice base in a shallow dish according to the size of the stain. Add the liquid cleaning agent to the flour 1 tsp at a time, working into the base gradually to form a paste. Set aside. Gently press a clean sponge dampened with water to the oil affected area. Apply the flour poultice to the area with plastic spatula or spoon. Cover with plastic wrap and press firmly. Poke holes in the plastic wrap with a toothpick or fork. Allow the poultice to dry for up to 24 hours. After 24 hours, remove and discard the plastic wrap and allow the poultice to continue to dry. Once completely dry, remove and discard the poultice. If there is still blood stain remaining, you may have to repeat the process. Once you are satisfied with the blood stain removal process, apply a small amount of neutral pH soap like Dove to a clean, soft sponge dampened with water. With a more porous natural stone surface, over-wetting should be avoided. Sponge the affected area to remove remaining oil residue. Once the entire area has been cleaned, remove the soap residue with a clean soft sponge, free of soap, wet with water. Use a squeegee to wick away extra moisture and avoid over-wetting and pooling that may damage your countertop and encourage build-up.
Stone materials of unknown origin, materials which have been dyed, materials which have been misrepresented by the vendor, or otherwise may react unpredictably or unfavorably to the poultice. Test the liquid cleaning agent on an inconspicuous location, including the sitting time, to determine its suitability and to make certain it does not discolor or otherwise damage the material. Familiarize yourself with the materials in and near the area you wish to clean to avoid damaging the material. Keep clean dry paper towels or soft rags at hand to promptly wipe up stray cleaner that has landed on an incompatible material. Natural stone countertops are best cared for with mild pH neutral products, and may periodically benefit from being re-sealed so that they can continue to resist stains and other substances that may corrode the counter's surface.
Caution: Never mix cleaning agents or chemicals, the result can be dangerous or deadly. Before cleaning, always test the agent on an inconspicuous location to determine its suitability and to make certain it does not damage the material. Wear appropriate clothing such as gloves and protective eyewear, and work in a well-ventilated area. Accidental inhalation or ingestion of cleaning agents can be hazardous and even fatal, particularly to pets and children.