I have had the exact same issue consistently for 2 years straight. I've had it off and on for several years before that, usually a lingering side effect from a cold or strep throat, but it would effectually go away. Not this time. I have no sinus issues, but I no longer have tonsils and get strep throat every few years (my doctor thinks one of my kids is a carrier). I have not been on antibiotics for over 3 years, so i can't rule out a long term bacterial issue. (Not even sure if they can linger that long?).

I am convinced my Silent Reflux is the current cause of my excess mucus. I also think those of us that have this dried plug form have a particular spot to harbor it, that maybe others don't. It's a bit of a perfect storm, which is why it may not be as common as it should be. I plan to see a Naturopath about my reflux, as i don't want to use the medication.

One tip i wanted to share is an easy way to dislodge the scab/ plug. Gargling! I lean my head waaaay back and gargle with warm water, almost swallowing it at the end. This could mean my "spot" where the scab forms is lower than other people's spot. Mine is right at the very bottom of the nasal cavity, right around the eustachian tube oriface. Hacking doesn't work (that brings stuff UP)... it needs to be brought down with a snort, and then coughed up. It almost feels like i just need to get it around a "corner" - like it's forming on a ledge. And it's attached to the ledge with very thick, sticky mucus, like glue! It's no wonder it can be hard to dislodge! But the gargling works. And so much relief afterwards! Until 2-3 days later when another one forms.

Interestingly, when I talk a lot - like in the phone, it dislodges itself! So the response to larynx activity suggests that it could be forming on, or very close to, my larynx. Sometimes it's slid down my throat, because I'm unable to get to a bathroom to cough it up. That is not fun!

Anyway, I'll post again after I've been to a Naturopath. I hope the gargling helps some people!