Expel the air by contracting your abdominal muscles. Avoid coughing or just clearing your throat. A deep cough is less exhausting and more efficient in clearing mucus from the lungs. Huff coughing: Huff coughing, often known as huffing, is an alternative to deep coughing if you are having difficulty emptying your phlegm. Coughing pills that contain codeine are available without a prescription. If you don't clear your chest of mucus, it will be trapped there and will eventually become infected. When you breathe in bacteria or a virus through your nose or mouth, certain cells near your nostrils and lips produce chemicals that signal other cells to create more mucus. The more mucus you produce, the harder it becomes for your lungs to breathe properly. This can lead to chronic bronchitis. The best way to get rid of mucus is to blow it out. Use your diaphragm to expel air from your chest cavity while at the same time squeezing your abdomen to force air out of your lungs. Coughing exercises can help loosen up stiff shoulders and thoracic (chest) regions due to overuse. Try moving your arms in wide circles as you breathe in and out rapidly, like a pump action gun. This will help you clear your lungs of mucus. Deep breathing exercises are also useful for clearing your lungs of mucus.