Ive Been A Smoker For Over A Decade 1&1/2 To

Ive been a smoker for over a decade 1&1/2 to 2 packs a day. I cough up brown stuff, it use to be occasionally but over the last month I've cut down significantly thanx to chantix. But since cutting down the brow comes all the time and is getting darker. I have uneducated guess like I'm coughing up tar or cancer. What do you think?