It costs to preheat the oven

Most things you bake don't really need a preheated oven. Save money and time by putting the food into a cold oven, then turning it on. Allow a little extra time, as the food cooks more slowly during the warming up period. (Not recommended for cookies or angel food cakes.)

Oven and grease cleanup

Put a half inch or so of ammonia in a shallow nonmetal container and leave it in a cold oven overnight. Fumes from ammonia is what does the job, so if you have grungy pots and pans, put them in there, too. The whole mess will clean up with soap and water and just a little elbow grease in the morning.