I began singing on stage at the age of 3.
That continued up until just a few years ago.
I am now just a few years beyond 50.
I have been a lover of smoking just about anything since I was around 14.
In my twenties I smoked nothing but Cannabis & took a few years off even from that.
Since my thirties I have smoked organic, whole leaf, non-filtered tobacco on a daily basis.
It has affected my singing voice somewhat, but nothing that I find too restricting or alarming (although, again, I am no longer singing professionally anymore).
I smoke Cannabis several nights a week & honestly I find that it affects my singing more than the tobacco, but that is just my subjective perception.
I freebase DMT once or twice every two or three weeks.
I have found the DMT actually seems to enhance my voice, but again, that is simply a subjective viewpoint.
The spitting you're experiencing is a good thing all in all. Everyone has crap in their lungs (whether they smoke or not) but very rarely does anyone spit it up or blow it out (the nose) which is the only way one can discharge the respiratory system of accumulated junk. Thus smoking can be beneficial in that you discharge more gunk from your lungs than if you didn't smoke. I know it sounds wierd, but it's a theory I've come to know as pretty close to the truth.
Some secrets that I have found to keep your respiratory system working in great shape while enjoying smoking all the while are:
Applying honey bee propolis to the back of the throat daily (I use a throat spray for this, but occasionally will suck on propolis lozenges or raw propolis if I'm lucky enough to get some from the local beekeepers). From decades of studying traditional plant medicines I've found very little that rivals the gentle, but powerful healing powers of propolis.
Traditional Chinese herb formulas for the lungs:
Look up & explore options such as: Bai He Gu Jin (Tang, San or Wan), "Lily Bulb Decoction To Preserve The Metal" ; Qing Qi Hua Tan (Tang, San or Wan), "Clear Lung Qi Transform Phlegm Decoction"; Bu Fei (Tang [decoction], San [powder], or Wan [teapill]), "Tonify Lung Decoction". To name just a few.
The lungs & the rest of the respiratory system (your sinuses, etc.) all like to keep moist & cool. Smoking anything introduces dryness & heat to the system & thus you must counteract the dry heat with cooling, moistening substances & formulas.
Hope this helps.:d