Never clean a smoker while it is hot or put water on it. Applying water to a stainless steel box can warp it. Use heat-resistant grill gloves or tongs and remove the smoker box from the grill. Let it cool before cleaning it. If the smoker box has creosote you can use this method to clean it How To Clean Creosote From Smoker/Pellet Grill-4 Best Ways