The ultimate way to get rid of blood or other body fluid stains is with peroxide. Just as you can see the action of peroxide lifting the dirt and blood off a wound, you can actually see it lifting off the blood stain. Naturally, it is still best to do when it is fresh if possible, pour the peroxide on full strength and use a little elbow grease to rub the stained area together, kind of between your knuckles. You can saturate pretty well as it will not harm any fabric I've ever used it on. I re-use an empty spray bottle from a commercial stain remover and I will often combine with a commercial stain remover as well.