An oven that is self cleaning has a feature that brings the oven to a high heat for a few hours and then automatically turns off to burn off any food spills or splatters from cooking. An oven without the self-cleaning feature requires a little more elbow grease, but thanks to modern oven cleaners, can also be cleaned effectively. Cleaning your oven once every month or so will help make the job easier each time.
Purchase a commercial brand oven cleaner. Pay particular attention to whether the cleaner is recommended for a cold oven or requires pre-heating before application. Both types work, it is just up to your preference.
Sweep any loose crumbs or debris out from the bottom of your (cold oven). Use a rough sponge or brush to loosen any burned sections. The less you have to clean out of the oven, the quicker and more effective the cleaner will be.
Pre-heat the oven if needed and turn the heat off. Apply the cleaner as directed by the manufacturer to the bottom and sides of the oven.
Allow the cleaner to sit as long as is recommended by the manufacturer (some require overnight cleaning, others are ready within a few hours. Pay attention to the instructions.)
Scrub the bottom and sides of the oven with the brush or sponge and scrub gently at any spots that do not brush out easily. Re-treat as necessary.
Wipe the entire oven down with a clean, wet cloth to help remove any remaining cleaner residue.