Not necessary. Over time, it will harden and get flaky; brush off the flakes. Of course,it you feel the urge, you can indeed clean off this residue. But it really is not necessary. Far more important to keep the bottom free of grease and oil which is why we foil the bottom and cover the wood box lid. And not there is an accessory secondary drip tray that fits snugly up against the walls of the smoker facilitating an easier after smoke clean-up.