Let the nasal wash solution drain fully from your other nostril so that it can help rinse out the excess mucus. Use only distilled water or filtered water using a filter with an absolute pore size of 1 micron or smaller or previously boiled water boil water 1 minute or 3 minutes if above 6 500 feet then allow to cool to body temperature. The sinus cavities are very small tunnels within the bones of your face.