Cleaning stove top burners?

mickietucs

I tried to search for this but didn't come up with an answer. Was wondering what can be used to clean the stove top "burners" (the 4 metal pieces where a pot/kettle sits) and the area where the flame comes out. I don't want to scratch the finish but they've blackened and I would like them to look new again. Can a brillo pad be used?
 

Nomad

Mine aren't dirty but are discolered - Think it's the heat discoloring the metal itself - Not sure that can be removed. Same with the flame vent thingy.
As far as the base, general spray cleaner makes mine look new.