Article in English: Take the bed sheet off the mattress first, then rinse the stain out using cold water. Do not use hot water, as this will set the stain. Follow this step with any of the stain-removal treatments listed below. Pour hydrogen peroxide directly onto the blood stain. Wait 20 to 25 minutes, then lightly pat the residue with a paper towel. If you don't have any hydrogen peroxide at home, you can use club soda instead.  White vinegar will also work in a pinch.  Light can turn hydrogen peroxide into water. If it is very bright in your room, cover the treated area with plastic wrap, then drape a dark towel over it. The towel will hide the area from light, and the plastic wrap will prevent the towel from soaking up the hydrogen peroxide. Simply spray the window cleaner onto the stain. Wait 15 minutes, then rinse it out from behind using cold water. Fill a spray bottle with 1 tablespoon of ammonia and 1 cup (240 milliliters) of cold water. Close the bottle and shake it to mix. Spray the mixture onto the stain and wait 30 to 60 minutes. Blot up any residue with a clean cloth, then wash the sheets in cold water. Be careful with colored sheets. Ammonia may fade or bleach colored fabrics. Mix  one part baking soda with two parts water to form a paste. Dampen the stain with water, then rub the paste onto the stain. Let the fabric dry, ideally in the sun. Brush off any residue, and then wash in cold water. Talcum powder or cornstarch/cornflour will also work. Mix 2 tablespoons of salt and 1 tablespoon of dish soap. Dampen the stain with cold water first, then soak it with the soap mixture. Wait 15 to 30 minutes, then rinse  the stain out using cold water. You can also use shampoo instead of dish soap. Fill a spray bottle with 1 part baking soda, 1 part hydrogen peroxide, and ½ part cold water. Close the bottle, and shake it to mix. Spray the mixture onto the stain, wait 5 minutes, then rinse it off. Repeat 2 more times, then wash the sheets in cold water. This works best on polyester-cotton blends. Use cold water, a mild...

Summary in Vietnamese:
Rửa vết máu từ mặt sau ga trải giường bằng nước lạnh càng sớm càng tốt. Xử lý vết bẩn với nước ôxy già. Thử nước lau trùi cửa sổ chứa ammoniac. Thử ammoniac pha loãng để xử lý vết máu cứng đầu. Thử muối nở. Hãy thử muối và nước rửa chén như một phương pháp xử lý vết bẩn trước khi giặt. Làm hỗn hợp tẩy vết bẩn từ muối nở, nước ôxy già, và nước. Giặt khăn trải giường trong nước lạnh sau bất kỳ phương pháp xử lý vết bẩn nào.