Seriously, it’s about time. Many ovens have self-cleaning functions, so all you need to do is set aside a few hours to run the cycle, and then be sure to wipe down the oven walls with a damp sponge afterward. If you don’t have a self-cleaning oven, you can use a harsh cleanser designed to clean ovens (follow directions, and wear rubber gloves!). Looking for a green solution? Make a mixture of baking powder and distilled white vinegar (or add enough water to it to fill a spray bottle) and apply to all surfaces; wipe down with a damp sponge or cloth. Always keep the kitchen well ventilated, and never clean an oven when it’s still hot or even warm to the touch; it should be cold.