Self-cleaning ovens use extremely high temperatures to burn off any food that spills in the oven. If you're having trouble getting part of your oven clean, natural cleaners such as baking soda or vinegar can help remove the stains. Natural cleaners won't affect your oven negatively.
Most self-cleaning ovens simply need to be closed, turned to self-cleaning mode and left alone until the cycle is over. When it's done, they're completely clean, and you can dust the bottom of the oven clean with a brush.
Some oven cleaners are explicitly labeled for use in self-cleaning ovens. They use chemicals that won't damage the interior of the oven. Never turn on the heat when using approved cleaners in your self-cleaning oven. Follow all package instructions.
Chemicals not meant for self-cleaning ovens can damage the interior of your appliance. The extreme heat in an operating oven transforms chemical residue into a compound that scratches the interior. Self-cleaning ovens aren't made to need chemicals. They become perfectly clean with only the self-cleaning feature.
If you've used chemicals in a self-cleaning oven, do not use the self-cleaning function before completely removing all chemicals from the interior. Use a sponge with water to wash all the chemicals away from the interior. Let it dry completely, then wash it again to ensure everything is gone from the surface.