After the holidays, our oven walls and get splattered with grease and such that eventually becomes stuck-on. Easily remove this gunk without damaging any self-cleaning features by filling a baking dish with 1/4 cup water and the juice of 2 lemons. Bake at 250° for half an hour. When cool, wipe off the walls with a damp sponge. The steam will have loosened any stuck on messes while the lemons removed any odor.