What Is the Difference Between Mucus and Sputum?

Mucus is this wonderfully healthy, slimy, see through stuff that actually has anti microbial properties. But when mucus gets combined with bacteria, itbe sputum. So i'm very specific about the difference between mucus an sputum because sputum then has these very um heavy properties and bogs down the silia. And doing airway clearance and keeping the airways clear is sort of like sending the police through a building that's kind of broken down.