Easy Oven Cleaning - No products The manual for my oven states that only warm water should be used for cleaning.

I've followed this so far but it is becoming increasingly difficult to keep the oven in a respectable condition.

Does anyone have any experience using natural options such as baking soda and vinegar, with ovens that require 'product free' cleaning?
Is it a self-cleaning oven? 

If so, running the cleaning cycle according to the instructions should leave nothing but a fine ash on the oven, which is easily removable with just warm water.