To start you are going to first clean your oven by wiping it down with a sponge and some very hot water. This will get a lot of the food pieces from the bottom, particularly if you have things that have fallen down. You can lift up the coil a little bit to get to anything that may have fallen below it while you were cooking. You may be tempted to use oven cleaner but a lot of self cleaning ovens do not work well with oven cleaner. Also oven cleaners contain very caustic chemicals that can cause breathing problems from the fumes, so you will want to be very careful if you use them. If you had something splatter in the oven that was greasy then you will want to go ahead and use some all purpose cleaner. You want to make sure that you rinse everything really well, particularly on the glass part of the oven door, because you don't want any chemicals baked into your food the next time you use the oven.