Pour 1/2 cup lemon juice plus 1/2 cup water in Pyrex or oven-proof glassware.
Place in microwave.
Put in for 6 minutes on high setting.
Open microwave oven--CAREFUL-IT WILL BE VERY HOT-- and it will smell wonderful, plus it will loosen any baked on food so you can easily clean up with paper towels.
Also, some of the mixture will have boiled over onto the bottom of your oven, but that's fine, you just soak it up with paper towels.
All natural, very affordable, and it works great!