Stuck-on food, grease and oil spills on a gas stove's cast-iron grates create nasty fumes and smells. These strong, heavy grates benefit from at least a once-a-month cleaning to keep your kitchen odor free while you cook. The methods used to clean them depend on how dirty they are.
Gather the supplies needed to clean your cast-iron grates and burn caps thoroughly. You'll need dish soap designed to cut grease, a nylon scrubber -- for enameled cast-iron -- a dishtowel, hot water and non-abrasive or powder cleanser. It helps to have a large sink or tub in which to put the grates, because you may need to soak them to remove cooked-on food stains. Put on a pair of dishwashing gloves to protect your hands from the hot water.
Loosen the Grease
Wait until the grates are cool to wash them; they're safer to handle, and they won't crack with exposure to water colder than they are. Once the grate cools, set it inside a sink or a tub and fill it with hot water. Allow the grate to soak in the hot water up to 30 minutes, long enough to loosen stuck-on food debris and cut through the grease. If you don't have hot enough water from your tap, boil water in a teakettle or in a pot; once it's hot, pour it over the grate set in the sink.
Wash the Grates
Add a squirt or two of grease-cutting dishwashing detergent to a sink filled with clean hot water. Set the grates inside the sink and allow them to soak for up to 15 minutes. Apply a non-abrasive cleaner to a wet nylon scour pad. Burnish the grates with the scrub pad and cleanser on hard-to-remove food spills. Repeat as necessary to clean the grates; set them back in the sink to soak for about five minutes or allow the wet cleanser to sit on tough spills outside of the sink to soften them.
Drain the sink and rinse the grates in cool water. Verify all the soap and cleanser are removed during the rinsing process. Once the soap and cleanser are gone, dry the grates thoroughly with a soft clean cloth to prevent rust. After you have removed all baked-on food and the grates are relatively clean, keep them that way by placing the grates inside the dishwasher and using the "pots and pans" setting. Remove the stove knobs and burner caps and add them to the top of the dishwasher with a load of pots and pans.
To remove stains on 100 percent enameled cast-iron grates, burners or caps, add them to a large sealable bag or container with a cover and 1/4 cup of ammonia to sit from three hours to overnight. Do not use this method on unfinished cast-iron.