To naturally whiten a T-shirt, sheets, towel or white T-shirt, some natural tricks are very effective.

Marseille soap
Formidable against stains, Marseille soap can remove the toughest stains. To use, simply wet the stain on your garment with Marseille soap and cold water. Rub gently to loosen the stained area and leave for an hour or two. Then, put your garment in the washing machine to restore it to its former whiteness. Prefer powder detergent for its bleaching properties. Also, air dry your garment to preserve the textile fibres.
White vinegar
White vinegar is a great product for the maintenance of white clothes. To stain clothes, start by diluting four tablespoons of white vinegar in water before soaking the stained garment. Soak for 1 hour and then rub the stain with a microfibre cloth. Then, pop your garment in the washing machine for a spotless result.
Baking soda
Baking soda is a real stain protector and helps to whiten clothes naturally. To remove yellow stains, you should make a paste with this famous white powder. Mix a few tablespoons of baking soda with water until a paste forms. Then, apply the paste on the stains and let it sit for 30 minutes before washing as usual. For stubborn stains, mix baking soda with lemon juice and rub with a cloth soaked in this solution. Let it sit for 2 hours and then machine wash your clothes.
Hydrogen peroxide
Hydrogen peroxide is an excellent alternative for cleaning white clothes. Also called hydrogen peroxide, this product has well-known bleaching properties and can remove yellow marks. To do this, remember to soak the stain with hydrogen peroxide and then leave it for 1 hour. Then rub the stains and put the clothes in the washing machine. Leave to air dry.
Soda crystals
Soda crystals can be used for cleaning purposes. For this, you just need to dilute one cup of soda crystals in one litre of water. Soak your clothes in this solution and rub the stains with a sponge to remove them. Remember to wear gloves during this manoeuvre to protect your skin. Finally, put your clothes in the washing machine and dry them in the sun.