@thumperguy I try to bring up mucus a few times a day. Sometimes it is clear, sometimes it is yellow (usually yellow first thing in the morning). I do this on purpose so I know I have not kept the excess mucus inside my lungs to provide sanctuary for bacteria. But I have not pondered its existence nor its colors. My take on it: as long as I don't have other symptoms that interferes with my normal daily living, I do not worry or even wonder about it. So far I have no symptoms that warrant concern and I'm as active as I want to be without any hindrance. So that is good enough for me.