Cotton is a natural material that contains tannin. Tannin turns sweat stains yellow.
How to clean: In a separate container, mix 1 teaspoon of citric acid or 1/3 cup of lemon juice with 1 cup of water.
Pour the solution into a spray bottle and apply to the contaminated area. Leave the product to act for a quarter of an hour, then rub it with a sponge or brush.
It is necessary to treat the stain with a product, leave for 15-20 minutes, then remove with a damp sponge or cloth. peroxide and soda.
The stain is covered with a layer of soda, a mixture of water and hydrogen peroxide is sprayed on top. Leave for 2 hours, then clean with a vacuum cleaner.
mix salt with lemon juice to make a slurry, apply to the stain, wait 2 hours and rinse with a damp cloth; apply soda on a fresh wet spot and leave it overnight, then collect the residue with a vacuum cleaner; apply diluted essence or 9% vinegar on the mark and wipe with a rag.
You can remove biological stains on children's mattresses with vinegar or citric acid: