How To Clean Blood from Painted Surfaces
Blood can stain even the darkest painted surfaces. If blood stains have occurred as the result of injury, make sure to resolve any safety issues prior to attempting to treat the stain. Where water is called for, use cold water rather than warm or hot to avoid setting the blood stain. Paint finishes and base materials vary widely, so test all cleaning solutions and application techniques in an inconspicuous location before using them in a wider area. For health and safety, use disposable materials to clean up blood stains or implements that can be easily disinfected.
Clean up and dispose of any bulk stain material with clean paper towels dampened with water.
Remaining blood stains on light-colored painted surfaces can be treated with hydrogen peroxide. The hydrogen peroxide may have a bleaching effect, and may not be appropriate for dark paints or specialized finishes. Use clean cotton swabs and cotton balls to apply hydrogen peroxide to the stain, replacing with fresh swabs or cotton balls as necessary. Follow stain removal by washing with a lightly sudsy solution of a mild pH neutral dish liquid diluted with water, applied with a clean soft sponge. Avoid over wetting, and allow the painted surface to dry thoroughly. If a large area was affected, you may wish to use fans to help facilitate drying and prevent lingering moisture that could encourage mildew growth.
Meat tenderizer is a good remedy to try on darker painted surfaces or specialized surfaces. Unseasoned meat tenderizer(with the active ingredient papain that will break down protein-based stains) and water can be mixed to make a poultice. To make the poultice, place 1 TB of meat tenderizer in a shallow dish. Gradually mix in water 1/2 tsp at a time to form a thick paste. Apply the poultice to the blood stain and allow to sit for 15-20 min. Wipe away and discard the poultice/stain residue using clean paper towels dampened with water. Follow with a light overall cleansing using a dilute solution of mild pH neutral dish liquid and water applied with clean paper towels. Follow with a clear water rinse. Avoid over wetting, and allow the painted surface to dry thoroughly. If a large area was affected, you may wish to use fans to help facilitate drying and prevent lingering moisture that could encourage mildew growth.
An enzymatic contact lens solution containing papain, such as Allergan's Enzymatic Contact Lens Cleaner, will have similar effects and can be applied as a liquid solution. These papain-based remedies are less likely to have bleaching effects than hydrogen peroxide, although any technique should be tested in an inconspicuous area.
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.