I started smoking on a masterbuilt GS40 propane smoker back in November 2014. I've only actually smoked at most 10 times. I decided to start up again. While recently smoking, I noticed a thick white smoke coming out of the vents. The meat doesn't really taste smoky anymore. Any suggestions? Also, I've been using wood chips in a cast iron skillet and they still burn out quick. Is it ok to use wood chunks in the cast iron? Any info. would help. Thanks!