With a water spray bottle and a sponge just spray lightly down everything just to loosen things up a bit. Mix a cup of baking soda, follow it up with a third of a cup of sea salt, add one tablespoon of liquid dish soap and then use water to create a thick paste.
Apply it liberally to the entire surface of the oven.
This will work to dissolve and break down the buildup on grates.
Once you’ve covered the entire surface leave it on overnight.
In the morning come down with a damp sponge, wipe down the surface and then rinse it thoroughly with water.