Rinse the stain with cold water as soon as possible
Mix equal parts white vinegar and water
Soak the stained area for 30 minutes
Gently rub the fabric against itself or with a soft brush
Apply liquid laundry detergent directly to the stain
Let it sit for 15 to 30 minutes
Wash the shirt in the hottest water safe for the fabric
Use oxygen bleach for white or color-safe fabrics
Make a paste of baking soda and water
Apply the paste to the stain and let it sit before washing
Avoid using chlorine bleach on protein-based sweat stains
Air-dry the shirt and check that the stain is gone before using heat
Repeat the treatment if the stain remains