Thanks for Grapefruit Seed Extract and irrigator tip. It does sound a plausible course of action as the Grapefruit-Seed-Extract (which contains an antimicrobial albeit synthetic) mixes with the mucos which in turn is eaten by the bacteria in the mouth and throat thus killing off the bacteria. I'm hoping this theory is correct and the Grapefruit-Seed-Extract is not just covering the problem as you suggested.
My symptoms are similar to yours; very bad breath (for nearly 20 years), intermittent nasal blockages especially at night, lots of thick mucos and post nasal drip, lumps in throat, dark circles under my eyes etc.
Years ago I thought it might be a sinus problem and I did a netti pot irrigation just with water. It did clear the mucos and my mouth did feel a lot fresher for a while but the smell was still, so I quickly gave up on that idea.
Since then I've tried the colon and liver cleansers, hydrogen peroxide (which I think has destroyed my taste buds lol), HCI, bicarbonate of soda, Antibiotics , the list goes on, and none of them has helped long term. Over the years I've been to numerous doctors,dentists, gastros, ents and the only thing I've learned is that I have a hiatius hernia and low iron levels, otherwise I'm very healthy! I know the hernia allows reflux which in turn causes the body the produce mucos in the esophagus to protect itself and this gives the bacteria more to feed on.
Another thing I've learned is that these so-called professionals are cowards. Not one of them has admitted to me that I have bad breath but they will sit behind their desks covering their nose or reach for a mask!! One even had the nerve to tell me that I was imagining it as he sat covering his nose - the t*at!
I recently decided to go back to basics and think sensibly about this BB problem because all this stuff I'm putting in my body can't be doing me much good. I discovered I had a sinus infection which I was totally unaware of except that I had a pain in my cheek above my back molars and I had ignored it for a long time. I took Neoxime Antibiotics and Flixonase nasal spray - I couldn't believe the amount of mucos and hard bits that came out of my sinuses the first time I used the nasal spray and the smell was horrendous. The nasal spray does cause a slight smell but this was really bad although it did lessen over time. I noticed the blackness around my eyes became a lot lighter.
I've come to terms with the fact that I have certain bacteria in my mouth that give off VSCs when they eat the mucos. I am going to concentrate on lowering and clearing the levels of mucos and killing off the bacteria without the use of Antibiotics and antihistamins although I will use the Flixonase nasal spray occasionally to clear my sinuses. I know lots of people who suffer with excess mucos and none of them have BB so in my case it is definitely caused by certain bacteria in my mouth.
So the search goes on ..... I'll let you know how I get on with the GSE.