There are a few things you can do to keep your smoker clean from one smoking session to the next. As with any cooking device, the grate or cooking surface should be kept very clean. For this reason I recommend using a wad of foil or a grate brush to remove any loose material. You can then run the grate or cooking surface through the dishwasher on the pots and pans cycle. They’ll usually come out spotless. If it’s been a while since you last cleaned your grates and there are lots of stubborn bits of debris between the rails, you can place them in your oven and run it through a self-clean cycle (assuming the grates will fit in your oven). This ramps the heat in the oven up to about 900°F and burns off the debris. The grates should come out clean and shiny.