Built up grease in oven

I've found the best way to get grease to loosen up in any oven is to place a glass or coffee cup of undiluted ammonia in the oven overnight. The ammonia vapors attack the grease, softening it. The next day:

1. remove the ammonia
2. mix it with a 2 cups of water
3. wear protective gloves
4. using a non-abrasive cloth or sponge wipe the grease off the surfaces.
5. switch to clean water only, wipe the oven one last time to remove the ammonia residue left by the cleaning.