An 18-quart roaster oven should be cleaned following every use. It is important that the roaster oven is turned off and unplugged before it is cleaned, as cleaning it while it is on creates the risk of electric shock.
The roaster oven should be cooled completely before cleaning begins and the oven should not be submerged in water at any point during the cleaning process. The pan, roasting rack and lid should be washed in soapy, hot water with a sponge or cloth. Everything should be rinsed well, then dried with a towel. Both the inside and outside of the roaster oven body should also be wiped with a damp cloth.
For trouble spots, such as stuck-on food, a mixture of baking soda, vinegar and water can be used. Once the reaction has occurred, the spot should be scrubbed with a sponge or cloth. Oven cleaner can also be used on a roaster oven; after the inside of the oven is scrubbed, it can be left to dry upside-down on newspaper. Ammonia can also be used to clean the roaster, but it is important to only use ammonia in a ventilated area.
When using strong chemicals to clean a roaster oven, it is important to ensure that all residue from the chemicals is removed before using the roaster to cook.