There are lots of kitchen cleaning products out there - many have chemicals that are corrosive and dangerous. Some have "natural" ingredients that may be safer. But think about what you want near what you EAT. How about something that you could eat?!
Cleaning stuck on gunk from your microwave can be done easily, with just water! Simply put a cup of water in the microwave and set to HIGH for 3-5 minutes. The steam will loosen up the food and you can wipe it down with a clean cloth. Easy as pie - and it works! (And, you now have some hot water - make yourself a cup of tea!) You couldn't make yourself tea with a sprayer of toxic chemicals. Now this is something you can feel good about :)
Also - I've heard some people recommend also adding 1 Tbsp vinegar to the water, but I've not found it necessary (vinegar water not recommended for tea, however!).