Cleaning the oven is a disgusting job that many of us put off until it is too late, and we really have to use the heavy duty, lung killing chemicals in commercial oven cleaners.
But here is an alternative that really works, even for really dirty ovens, and leaves your kitchen smelling pretty for a few days after!
Heat your oven for 5 minutes - I usually put mine on 200oC - then turn off. While waiting for the oven to cool, put ¼ cup of laundry powder mix with enough white vinegar to make a paste. I also add a little baking soda to the mix as this really helps to breakdown grease and also neutralise odour.
Spread the paste evenly around the oven, on the walls, ceiling and base of the oven and leave for an hour, although I like to leave mine overnight until it sets.
Using wet clothes, and occasionally a green scrubber, wipe off the paste. This should take the worst of the grease with you. Make sure you wash the walls really well, because when it dries, there will be a film of white.
Your oven will smell like your laundry for a few days after use, but it doesn't affect the taste of anything you cook in it.
One really helpful tip - as long as your oven isn't self-cleaning - put tin foil or a silver tray in the bottom of your oven. This will help reduce the amount of cleaning you have to do on the base of your oven.