Those yellow, sweaty stains are the pits. Underarm stains are an equal opportunity culprit, ruining as many male shirts as female blouses (and dresses). The good news is that it’s easy to remove underarm stain and odor from any fabric, here’s how.
Get the Yellow Out
The yellow stains are caused when sweat and antiperspirant build up on fabric, get the build up off and the stain comes out. Start by rinsing the underarm stain for 15 seconds with cool water. This will dilute the body salts and acids trapped in the fabric and should also be done to garments that are sent to the dry cleaners (let air dry before sending to dry cleaners).
Work some enzyme containing liquid laundry detergent, like Tide , into the wet underarm fabric, then let set for 15 minutes. Follow by washing the garment in the hottest water that is safe for the fabric and add a color safe, dry bleach product to the wash water (some enzyme contain laundry detergents already contain color safe bleach, if your doesn’t Clorox dry bleach will work).
After laundering, check the garment before placing in the clothes dryer. If the underarm stain is still visible, treat stain and re-wash before drying. Once the garment is dried in the dryer, the stain will be set and will never come out.
Get the Odor Out
Sweat does not stink, it’s the bacteria on the skin that creates the stink, according to BBC Health. Bacteria which normally lives on skin breaks down the sweat and that process gives off a unpleasant odor which fabric absorbs.
To get mild odor out of underarm fabric, add a cup of baking soda to wash water. To get out more stubborn sweat odors, add three tablespoons of table salt to a quart of warm water, then soak the odoriferous garment for one hour, followed by the usual machine laundering. The salt will help kill the bacteria, which is the root cause of the odor.
Help Prevent Underarm Stains
Use antiperspirant sparingly and let it dry thoroughly before dressing. Applying antiperspirant the night before works even better to prevent garment staining. The product will remain intact during a normal soapy shower, but underarm shaving will remove it. Use a solid stick antiperspirant – deodorant product instead of a roll-on or gel, fabrics absorb the latter much more readily.