Blood stain removal can be one of the most difficult cleaning processes, and depending on the surface and type of material stained, there are a number of different techniques that can be used. One of the most important things to note is that if the material that is stained is something like clothing or carpet, it is vital to use only cold or cool water and not apply heat to the stain. Heat will cook the proteins in the blood just like in meat, and the stain will be set and just about impossible to remove. In general, the best approach to blood stain removal is to use a mild mixture of soap and cold water, with a towel or sponge and blot rather than rub the blood in further.
The best methods for blood stain removal depend a great deal on the surface or material that has been stained. Typically, clothing is one of the most difficult materials when dealing with a blood stain. Anyone attempting to remove blood from clothing should carefully read any handling or washing instructions on the garment to ensure the article is not damaged during blood stain removal. Afterward, the garment should be allowed to air dry in case the stain was not completely removed, as heated drying will set the stain.
One of the best ways to remove blood is with a mixture of diluted ammonia or soap in water, which is then carefully applied and blotted repeatedly until the stain is “pulled” out of the fabric. Ammonia should not be used on delicate or animal-based materials such as silk and wool, as it can seriously damage the material. A mixture of baking soda and cool water can also be similarly used, as well as hydrogen peroxide. If peroxide is used then it may stain or bleach fabric, so it should be used very carefully and not be applied outside of the stain area.
Since blood is similar in many respects to meat included in many people’s diets, the same products used to clean meat off dishes can often be used in blood stain removal. Detergents and dishwashing solutions that contain enzymes for breaking down meat can often remove blood quite well. Similarly, meat tenderizers often contain these same types of enzymes that can break down blood stains as easily as a tough steak. These can be used in a small solution of cool water and applied like any other cleaning product, though again care should be taken with silk and wool.
Saliva also contains similar enzymes and a small amount of saliva can be applied for small stains from a bloody nose or lip. For carpet, a solution of baking soda and water, applied lightly then blotted, taking care not to push the stain in further, is usually the best method of blood stain removal. On plastic and metal, some warm water can usually be used with a damp rag to rub or wipe the stain off.
On leather or suede, a solution of mild soap in cool or lukewarm water should be prepared and stirred until bubbly. Only the foam should then be carefully applied to the stain area, then a damp cloth should be used to wipe away the stain and cleaner. It is also important to note that if the blood is somehow related to a criminal act, then the removal of the blood stain may be considered tampering with evidence and be illegal.