I've found the main factor in cleaning the racks & grills is the hotter the water the better. I use both dishwasher (Cascade) & dish soap (Joy) together with hot tap water & a kettle of boiling water to soak the racks in. When I add the boiling water into the soapy water, you can see gunk on the racks start to melt away. I first soak the racks while wiping-down/cleaning out the smoker, and by time that's done the soak water has cooled down enough for me to simply brush-off the racks, rinse them, and they are good-to-go for the next time.