Nasal saline sprays are used to moisturize and clean the nasal passages. They can be used for relieving congestion and dryness, as well as washing out allergens and other particles from the nasal passages. They are also helpful for thinning mucus and easing breathing for those with allergies, colds, or sinus infections. Nasal saline sprays can also be used as a preventative measure to keep the nasal passages clear and healthy.