Thanks! I will try that.

How did you happen to discover this method?

Are your grates painted gray or gray cast iron?

Mine are not in such severe condition; but have you try putting them in your dishwasher yet?

My stove is a Maytag double oven (I think it is called 'Gemini'. It is three years old and I use it daily. Yes, the grates are caste iron -- can't imagine what 'painted' means. The dishwasher is useless unless you put them in there daily and who does that?

I will tell you that before I found the great ammonia hint, I ordered black grates and with shipping, it was $100. That was worth it to me because the ammonia method takes a over-night process and I now have a second set.

I've also had great success with melamine-foam pads. They're available under the Mr. Clean Magic Eraser and 3M's Scotch-Brite Easy Erasing Pad brands, and, probably, others.

The Magic Eraser works pretty well on the top of the stove around the grates. It isn't very easy with baked on grease on the grates. Believe me - this method just softens everything. I think it probably would work well with caste iron cookware also.

I have used ammonia for years and have found the best way is to put the the grates individually in strong plastic bags, then in plastic tubs. Put the grates in upside down in the bag, add about 1/2 cup ammonia to each, seal the bags and let sit overnight. Then use your scouring pads to clean.

Cindy nailed it! The hardest to reach, most baked on, carbonized little bits (and everything else) will literally wipe right off after a night in an ammonia bath. It's not a trick for everyday maintenance, but when you really want to get the grates looking like new, give it a try...and you'll never pick up a scrubby again....well, not at least to aim it at a cooking grate.

And it's OK for cast iron, no rust or other problems?

With caste iron, you are only leaving it in the ammonia overnight. Next day, you scrub wash, dry and re-season.

The same trick works with your oven racks too!

We used to use it when I worked at a restaurant.

Remember, remove your oven racks and clean them with this method instead of leaving them in your oven on self-clean. The self-clean feature will destroy them.