how do i clean my headliner?????? Options

[SAMIAM]

so my celi's sunroof has been leaking water on me every time it rains. i removed the headliner and cleaned the drains out. did some water draining tests and everything looks good. the question i have though is since i have the headliner totally out of the car and im a dumbass smoker, it would be nice if i could give it a good cleaning. it doesnt have any cigarette burns which is good but it is pretty stained looking on the drivers side. im guessing from smoke residue, but again no burns. so besides quit smoking, does anybody know a safe way of cleaning it without scrubbing the felt off or otherwise making it look worse?