Fill a clean sink with warm water and add several drops of dish soap. Use your hand to swish the soap and water together. Submerge the iron grates in the water and scrub with a nylon scrubber before rinsing the grates with cool water. Alternatively, run the iron burners through the dishwasher.
Cover a baking sheet with parchment paper or aluminum foil. Preheat the oven to 350 degrees Fahrenheit.
Pour a small amount of cooking oil in a bowl. Saturate the bristles of a pastry brush in the oil. Apply a light coating of the oil onto the iron grates.
Set the cooking oil-covered iron grates on top of the baking sheets. Bake the iron grates in the oven for 10 minutes.
Let the iron burners cool before placing them back on the cooktop.
Dampen a clean sponge in warm water and sprinkle baking soda over one side.
Wipe the cooktop with the baking soda-covered sponge until the surface is clean. Remove the baking soda residue by wiping with a damp cloth.