 Yun Chuan and Sing Pao. The International Union for Conservation of Nature saying today 45,000 species are now threatened with extinction. You're listening to ABC News. Why is Navaj perfect for allergy sufferers? Rhino Systems Medical Director Dr. Howard Levine explains. If someone's exposed to allergens, they can get rid of those immediately by washing out the nose. Navaj works by pulling saline in one nostril, through the nose and out the other nostril, sucking out allergens, mucus, dust and germs.