There is an answer to this question but you’re not going to like it! The only way to keep your oven permanently clean is to wipe it around with a sponge and soapy water after each use. Obviously this is not always practical as you probably want to eat the food you have just cooked. Also the oven is hot and you need to leave it for 20 minutes before touching the inside.
It is important to remove any fat or food before it turns solid and become carbon. Once this process takes place it is then very hard to remove. Instead of trying to clean your oven on a daily basis, just contact Oven Ready on a 6 monthly basis and ask us to come and clean your oven for you.