If you ignore them, the stove burners and the grates can end up looking disgusting and nobody wants that in their kitchen. So what can you do? It’s simple actually. Clean the stove with ammonia. Take ¼ cup of ammonia and seal it up with one of the burners in a plastic bag. Let it sit overnight and then it should wipe clean with a sponge.
Clean Your Gas Cook Top Burner Grates from Food.com: I had tried most everything to clean the porcelain enamel grates on my cooktop with little success. Then I read the use & care guide that came with the cooktop. How simple is this! NOTE: I used a plastic trash bag with a tie top. When entering this "recipe", a plastic bag wasn't recognized but a ziploc was. Ignore that "ingredient" ;-)
slip grate into gallon size ziploc bag. Do not put any holes in bag. Pour 2-3 T. ammonia into bag. Seal bag & let sit for 12 hrs. Do this overnight. Take grate out of bag in kitchen sink. Rinse the grate thoroughly and scrubb with a nylon scrubber.