A mucus clearance device is a handheld, non-medicated tool used to loosen and clear excess mucus from the lungs. It works by having the user exhale through the device, which creates vibrations or positive pressure that helps dislodge mucus from the airway walls. These devices are commonly used by individuals with chronic lung diseases like cystic fibrosis, COPD, and bronchiectasis to help with breathing, reduce congestion, and prevent infections.