Why do my AC vents smell musty and how can I get rid of the odor?

Musty smells in AC vents are often caused by mold or mildew growth due to moisture buildup. To get rid of the odor, you can try cleaning the vents with a mixture of water and vinegar, changing the air filter, and running the AC on high heat to dry out any moisture. If the smell persists, you may need to have a professional inspect and clean the ductwork.