That forgotten box of baking soda in the back of your refrigerator or pantry is more useful than you think, especially when it comes to your beauty regimen. Baking soda, or sodium bicarbonate, does double duty for a lot of more expensive beauty products, so why not start storing that great little box in the bathroom? Begin with your hair. Baking soda, when shaken onto a brush, can freshen up oily or limp hair that needs washing. Styling products, such as gels and hairsprays, cause buildup on brushes, which can be cleaned up in a jiffy with a soak in baking soda, bleach and warm water. You can even add a teaspoon of baking soda to your regular shampoo to get hair squeaky clean and buildup-free. Many toothpaste manufacturers include baking soda in their products, and for good reason. It makes a perfect tooth whitener, even when used alone on a toothbrush. Make a paste of baking soda or shake it onto a wet washcloth for an effective face scrub, and use it anywhere you have rough skin - elbows, hands, knees and feet.