Remove the oven grates and let them cool completely
Fill a bathtub, large sink, or tub liner with hot water
Add dish soap or a degreasing cleaner to the water
Submerge the grates and soak for several hours or overnight
Scrub the grates with a non-abrasive sponge or brush
Use baking soda paste on stubborn buildup
Rinse the grates thoroughly with clean water
Dry the grates completely with a towel
Reinstall the grates once fully dry