How many white clothes have you thrown over the years because they had circles because of sweating?
However, we can bring back whites to yellowed armpits following this small recipe.
In a bowl, mix 1 part liquid dish soap and 2 parts peroxide (the one used for cuts) and mix.
Apply this paste to stained areas and sprinkle with baking soda.
With a small brush (eg a toothbrush), scrub the entire surface to be cleaned.
Let it stand for an hour or two, then wash it normally at the machine.
It will be white as new!