The answer to 'how to clean air duct' is to have your air ducts professionally cleaned every 3-5 years. Air ducts can accumulate dust, debris, and even mold over time, which can reduce air flow and indoor air quality. Professional duct cleaning involves using specialized equipment to thoroughly clean the entire duct system, including the registers, vents, and air handler.
If you notice reduced airflow, increased dust in your home, or musty odors, it may be time to have your air ducts cleaned. However, it's generally not recommended to attempt duct cleaning as a DIY project, as it requires specialized tools and training to do it properly and safely. Attempting to clean the ducts yourself can actually dislodge more debris and spread it throughout your home.