We have a GE gas range w/ gray grates on which the pots and pans sit. They get black gunk burned on them (not overflow from the pots) and are a royal pain to clean! The GE people said to put them upside down in a garbage bag with household ammonia over night then they should clean easily. Well, it sort of worked, but what a major inconvenience - and mess! Is there a miracle agent out there like WD-40 (BTW it doesn't work for this) that will clean these things? Help!

Oven Off (oven cleaner) instead of putting the grates upside down just place right side up and follow the directions on the can of Oven off.

Alternatives would be using a bit of bleach water, OR using vinegar water.

Soot is caused by an improper flame usually the gas to air ratio is off or you are cooking in a gale (wind) area.

If you have propane then soot comes with the territory, and you have to readjust and use the proper LP valves - but then just walking by the stove while on will cause soot.

Gunk is usually a mix of soot and splattered grease/oil - even if you are a careful cook any frying 'steam' will contain droplets of grease/oil. Ideally after each time you cook you should wash your stove top and its burners with soapy water.

Practically you can use burner covers to prevent grease from getting on the unused burners. For an idea: http://www.jmcutlery.com/BurnerCovers.htm

I use an old flat cookie sheet.

I also use a square of 1/4 inch steel plate - However that is my heat sink, I place it over a burner to spread out the heat evenly for many things I cook.

I also have a GE gas range and, assuming our burner grates are similar, I use S.O.S. pads and hot water- 5 years now and no damage to the grate finish... on the silly little burner bibs, I use oven cleaner because those WILL scratch and the finish will crackle if scrubbed hard or with an abrasive cleaner.