Cleaning Porcelain coated cast iron gas grill

Clorex bleach

Wrap with paper towels, soak down with straight Clorox bleach then put in a bag so it stays moist over night unless you can find a plastic tub to soak them in. I have used bleach in the bottom of my porcelain pots when they have burnt on food for years and it works great. The bleach eats the enzymes and the burnt just disappears over night.

Amonia

Individually wrap the grates in several layers of newspaper. WORKING OUTDOORS, soak the newspaper in household ammonia (water) with or without soap. Immediately slip the wrapped soaked grills in a single heavy-duty plastic garbage bag, fold over the end, and leave outdoors, overnight. BE CERTAIN TO STAY UPWIND FROM THE AMMONIA! (You are probably better off doing this on a concrete or masonry surface, and NOT grass!)

The next day, remove the grates and hose them off. Then scrub them (use a bristle brush) with soap (or liquid dish detergent) and water. Hose them off again.

This will (supposedly) clean them!

Amonia (easier)

The easy way to do the cleaning, I have done. I put the oven parts (which were really bad, cleaning after an "unclean" home owner) in a heavy trash bag. No wrapping or any such thing needed. I took the parts outside. I poured a pint of ammonia in the bag and sealed it. The next afternoon, I opened the bag, took out the parts, and rinsed off the cooked on crud.

Source: Ann in Arkansas@Canning2

"self-cleaning" oven

If your oven is "self-cleaning", put the grates in it, and start the cleaning cycle.

Oven cleaner

Again, OUTDOORS, set the grates on a large flattened plastic bag, and spray with Easy Off oven cleaner. WARNING: this is a highly corrosive sodium hydroxide spray -- use rubber gloves and eye protection! Again, stay upwind! After the package recommended time, hose off, and scrub, using clean wash water.

Gunk

Heavy duty plastic garbage can. Boiling water to cover. Put the lid on and let them soak. If I've found some 409 on sale, I'll dump a bottle of that in. Then I rinse them off and use a wooden spatula to scrape as much gunk off them as I can. Then I put them on a tarp and use Gunk. It is an engine degreaser and works wonders! After they soak in the Gunk, *usually* everything comes off. Then I put them back in the garbage can with more boiling water and some dishsoap to cut the Gunk and they are as good as new!