Underarm-Lightening by Underarm-Lightening Underarm Lightening This is a simple technique to remove dead skin cells and lighten the skin. Works great for underarm areas and knees. Items Needed: Sliced Cucumber 2 tbsp. Olive Oil 1 tbsp. Baking Soda 3 tsp. Lemon Juice You don’t need to use a whole cucumber, as a few slices will be enough.In a medium bowl, add ingredients and mash & mix together until pasty. Apply to areas you want to lighten, underarms, legs and knees. After about 10 minutes rinse with lukewarm water and pat dry using a soft cloth.