Cleaning a stove/grates

So I have a nasty old gas stove.  I may have mentioned before how much I hate this thing but if not let me say right now, IT IS THE BANE OF MY CLEANING LIFE RIGHT NOW.  No matter how hard I scrub.  No matter how fast I get to it I can not get the black burnt circle off one of the dang thing.  So I thought I would try this remedy for the grates on the whole stove top.  I did exactly what she did (except I put my stove top in a garbage bag instead of zip lock) and put them on my patio over night.

Source: pinchingyourpennies.com via Leslie on Pinterest

 In case you don't want to look at the blog she put her stove grates in zip lock bags with a 1/4 cup ammonia for 12 hours and then the scuz just wiped off.  So I did that, and then did it bigger with my whole removable top in garbage bags tied up.
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Well it worked on the grates.  It helped on the stove top but not by much.  Oh well.  Any ideas?  I'm about ready to throw in the towel and except defeat.