I would be more concerned with food taste. It sounds more like not enough air is moving. Try opening up your airflow would be my thought. There are many types of drum owners on this site, meaning many different opinons. My rule is use more airflow, and counter with more mass inside. Smoker plate, water pan, and most important plenty of food in the cooker. Works for us. We also clean and spray with some form of oil. Olive, veg., corn after every cook. Usually cleaning means brushing grills, blowing out with compressed air, wipe down and spray with oil. It is normal to have some coating, but not enough to build up and flake off. Good luck, Steve.