====== Remove pit stains ====== Pit stains are either armpit sweat and salt residue or sweat mixed with deodorant aluminium. To remove: - soak stain at least 10 minutes with undiluted distilled white vinegar, then wash with biological detergent. - apply a paste of 3:1 ratio baking soda and water to the stain and rub it in with a brush, then wash as normal - add 1/2 cup of baking soda with regular detergent to whiten, freshen, and soften fabrics.