How to clean your oven - Heat oven to 60. Boil a pot of water. When the oven reaches 60, turn it off. Put 1 cup ammonia on the top rack, the hot water on the bottom rack, close the door, and leave overnight. The next day, open all doors & windows, remove and keep liquids. Leave the oven open for 15 minutes. Add 1 tsp dishwashing soap (with NO bleach) & 4 cups hot water to ammonia. Wear kitchen gloves. Wipe clean with ammonia water.