I also have COPD and handled the problem by using nebulized acetylcysteine. That breaks up the mucus. Also, because of the
albuterol and Duoneb that you might be using with an inhaler or nebulizer, this causes thrush, a fungal ailment, that starts in the mouth but can extend to the sinuses and lungs. Stay away from sugar, bread, and carbohydrates in general. These are foods for fungus that causes mucus.