Why do i have coloured drool every morning when i wake up?

[hereoto]

Hello
I have had this condition for SIX years and still have no clue whats wrong. Been through a few general health checks including X Ray and nothing odd showed.
basically i drool almost every night which is gross but fine, however my drool is very foul and dark coloured. fortunately i sleep alone but it gets embarassing when i travel or when i get lucky.
I'd like to know what on earth could be wrong and if there was something really wrong i would have known after 6 years.
anyone else goes through this, any remedies?

i am a smoker and drinker although i cut down on cigarettes for the past 5 months.
i am omnivorous but in the past year i was diagnosed diabetic and am working to reverse my condition (and its improving according to the doc i saw yesterday, when my blood sugar dropped from 15 to 7 in a few months)
i feel better the past 3 months than the past 8 years combined so my health is on the up, just this annoying drooling thing is bothering me.

any thoughts appreciated

[Morpheus1517]

In addition to a general medical doctor reviewing this, you might also consider getting an opinion from a dentist and an MD who specializes in ear, nose, and throat.