You Will Need 2 tbsp baking soda 1 tbsp water Prep Time 2 minutes Treatment Time 30 minutes Method In a plastic or glass bowl, combine the ingredients until you get a thick, coarse paste. Alternatively, you can mix the baking soda with rosewater. Apply this paste on your underarms and massage your armpit in circular motions for about 5 minutes. Let the paste stay on for an additional 25 minutes, after which you can rinse it off with lukewarm water. How Often? 2-3 times a week.