BLOOD STAINS AND HOW TO GET RID OF THEM Bloodstains Dried-on blood is one of the hardest stains to treat because most washing powders don't remove protein (same goes for sweat). Use a mix of one part white wine vinegar to three parts of water and blot the solution onto the stain until it lifts. Rinse well with cold water. Use cold water, as hot water will'set' the stain. If you have no vinegar to hand, spit! Saliva contains enzymes that will break down the protein in blood. Use your finger to loosen the stain and rinse with cold water. Finish with detergent as soon as possible. If the stain is fresh, soak immediately in cold water.