Stains that result from sweating are unsightly and weaken the clothing's fabric. The unpleasant odor associated with these stains does not always go away. Initially, sweat is acidic and can be removed by immediately washing the article of clothing. If you don't take care of the stain right away, it dries and goes from being acidic to alkaline, and most cases forms a yellow or green stain with a hard texture. Cleaning sweat stains from black fabric can be taken care of with common household products.
Apply liquid laundry detergent directly onto the sweat stain. Gently rub the detergent into the stain and allow it to sit for 30 minutes. Wash the black fabric as you normally would.
Mix 1 tbsp. of vinegar with a 1/2 cup of water. Dip a sponge into the mixture and apply it to the sweat stain. This will restore the color and remove the stain and smell.
Mix 1 tbsp. of baking soda with water until a paste forms. Spread the paste all over the sweat stains and leave it on for 20 minutes, then wash the black fabric as normal.