Treat the bloodstain as quickly as possible, giving it as little chance to set as possible. Do NOT rinse with hot water, which will only set the bloodstain. Instead, treat only with cold water. Assess whether the bloodstain is fresh or dried and old. If the bloodstain is new then flush the stain with cold water, and then soak in cold water for approximately half an hour. Then, apply 3% hydrogen peroxide directly to the spot with an eyedropper. If the blood stain is dried, first brush off all dried blood. Then, create a soaking solution of cool water and a laundry detergent that contains enzymes to soak the stained item in for, at least, 30 minutes or, perhaps, longer (up to overnight). After soaking, pre-treat the stain with a laundry prewash stain remover. Launder as normal. Make sure the stain is gone after washing, but before you place in the dryer or you may set the stain. Repeat if necessary.