Ovens are subject to all types of spills, stains and food residue that make their way onto interior surfaces during the cooking process. Burnt-on foods like sugar can be particularly difficult to remove, as they become more firmly attached to the oven when heated. Sugar forms hard, cement-like globules that may need special attention to remove. Getting rid of burnt-on foods like sugar from your oven requires a process of trial and error, and some basic home cleaning supplies.
Put on rubber gloves. Slide your oven racks and grills out of the oven. Slide the grills until they no longer move, then lift up slightly and lift them from the mounting brackets on either side of the oven interior. Place your oven racks and grills in the kitchen sink. Use steel wool cleaning pads, dish detergent and warm water to remove burnt-on sugar from the surface of the racks and grills.
Dip a clean rag into ammonia until it is saturated. Place the rag on top of the burnt-on sugar wherever it is on the oven surface. Allow the ammonia to penetrate the burnt-on sugar for about 30 minutes. Remove the rag. Wipe down the oven surface with warm water and a clean rag.
Preheat the oven to 150 degrees Fahrenheit, then turn it off completely. Pour 1/2 cup of ammonia into an oven-safe cup or bowl, then rest it on the center shelf inside the oven. Fill a large baking pan with boiling hot water and place it on the bottom rack inside the oven. Close the oven door. Do not use the oven for at least four hours, or as long as overnight.
Open the oven door. Remove the bowl or cup and the baking pan. Allow the ammonia smell to dissipate from the oven interior. Mix 1/2 cup of ammonia with 1 quart of warm water. Soak up the mixture with a kitchen sponge, then use the sponge to clean off the burnt-on sugar. Rinse the oven interior with warm water and a clean rag to remove any ammonia residue before using.
Remove the broiling pan, racks and grills from your oven to prepare it for self-cleaning. Use a damp rag to remove any dirt or debris from the oven door seal and edge. This dirt can prevent the door from sealing properly and compromise the self-cleaning process. Remove everything from the top of the oven. Follow the oven manufacturer's instructions to start the self-cleaning process.
Use a commercial oven cleaner to remove burnt-on sugar on oven surfaces that are not stainless steel. Use the cleaner according to the manufacturer's instructions.