Even with a self-cleaning oven, the grates do not come as clean as I’d like. If you have the same problem, you can remove the built-on gunk by coating each grate with coconut oil. Let this soak in for about a half an hour. Now, rub baking soda on the grates using a toothbrush. The dirt will come right off. The coconut oil will have dissolved any coking grease while the mildly abrasive baking soda removed stuck on food.