Underarm stains are caused by the reaction between the salts in your sweat and anti-perspirant ingredients. Removing these stains from clothing is a process that can take about 30 minutes before allowing to dry. In order to remove perspiration stains from your clothing, you need baking soda, hydrogen peroxide, water, a towel and a soft toothbrush.
Mix your cleaning solution, and prepare your work area
Pour about 1/4 cup of baking soda into the container. Mix this with an additional 1/4 cup of hydrogen peroxide, and give the solution some time to blend. During this time, you can lay your dry towel on a flat surface to prepare your work space.
Work the solution into the stains
Lay your dirty clothes down on top of the towel. Using the solution you have mixed, gently rub these stains. You need to give the solution some time to work on the clothing, so wait for about 30 minutes before moving on to the next step.
Brush clean and wash
Using your toothbrush, brush the clothing over to see if there is any leftover residue from the cleaning process. Once the residue is gone, remove the clothing from the towel. Make sure you have washed the clothing as usual at least once before you wear it again.