There is a simple way in which you can clean your oven.
1. Remove everything from the oven such as racks, pizza stone, thermometer etc.
2. Put on gloves to protect your hands and apply your oven cleaner to the insides of the oven.
3. Let the cleaner sit for around 20-30 mins but always check the label!
4. In the meantime, take the oven racks outside and clean them with the same oven cleaner
5. Then, take a damp cloth and wipe down the inside of your oven
6. Rinse your racks and place them back into the oven when dry.