- Spray stain remover on any dark underarm stains that you see on the shirt. Wait 30 minutes while the stain remover soaks into the fibers. If you notice that the stain remover is starting to dry, spray more on to keep the area moist.
- Pour 1/4 cap of detergent directly onto each underarm, on top of the stain remover if you used it. Rub the detergent into the fabric.
- Set the washing machine to fill with warm water, and pour the rest of the cap of detergent into the water. Add 1/2 cup of borax or washing soda to the water, and then drop the shirt into the washer. Stop the washer when the water is done filing the machine, and let the shirt soak for another half hour.
- Turn the washing machine on again. At the end of the cycle, check to see whether the stains are gone. If the stains are still visible, repeat the entire process. If the stains are gone, dry the shirt according to the shirt's care-label directions.
Things You Will Need
- Stain-remover spray (optional)
- Heavy-duty liquid laundry detergent
- 1/2 cup borax or washing soda (optional)
- Washing machine
- Wash perspiration-stained shirts as soon as possible to prevent permanent damage.