Tomato has skin brightening properties and it also helps detox the skin and lightens it as well. It is anti-inflammatory so it also helps calm down razor burns. Baking soda, on the other hand, helps exfoliate and scrub away dark dead skin and reveal new brighter skin.
Take a smaller sized tomato and cut slices out of it. Now, take some baking soda in a bowl and dip one side of the tomato slice in it. Rub the slice gently on your armpits until the sugar dissolves and tomato gets mushy. Wash off and pat dry.