Remove the baking racks. (we'll wash these separately)
Mix the baking soda with the water to form a paste.
Coat the inside of the oven, minus the heating element.
Sprinkle a thin layer of salt over the excessively grimy areas.
Let it sit for at least an hour before removing it with a plastic scraper or cloth.
Part II
Combine vinegar water and lemon juice in a spray bottle.
Spray the mixture over the entire inside of the oven, including the glass. (again, avoid the heating elements)
Let it sit for a few minutes before wiping it clean with a dry cloth.
Notes
Use the same baking soda/water mixture to clean the oven racks. Let it sit up to 4 hours before scrubbing clean with a scouring pad. Or take it outside to wash clean with a garden hose.