Underarm perspiration has a way of striking without warning, often when it's least convenient or most embarrassing for you. If you're away from home, you might not be able to put your shirt through the laundry -- or maybe you forgot to wash your shirt and it's a necessary part of your job. That doesn't mean that you're stuck with a smelly shirt. Inexpensive supplies, such as baking soda and peroxide, contain odor-fighting properties that knock out body-odor stains without the help of a washing machine.
Dab the underarms of your shirt with a dry paper towel as soon as you notice perspiration soaking into the fabric. If you act fast, you may prevent the sweat from building up and causing a bad odor.
Moisten a cloth with 3-percent hydrogen peroxide, then blot the shirt's underarms with the cloth. Peroxide breaks down body odor and bleaches sweat stains without laundering. If your shirt is made of wool, rinse the peroxide out a few minutes after applying to avoid damage. Do not use peroxide on your shirt if it is made of delicate fabric -- such as cashmere, angora, silk or some other type of animal hair.
Mix equal parts water and lemon juice, and apply the lemon water to perspiration stains. The lemon juice cuts through sweat stains and deodorizes fabric.
Combine 4 tablespoons of baking soda with 1/4 cup of warm water. Rub the mixture into stains. Allow it to sit a few minutes, then rinse with lukewarm water. Pat dry with a towel. If you don't have time to do this, just dab a pinch of dry baking soda on the inside of the shirt's underarms. The baking soda also helps keep your armpits dry and odor-free.
Mist the stains with a store-bought fabric-deodorizing spray. Most sprays also contain a fragrance that helps cover up odors.