Cleaning a Cast Iron Grill in 6 Steps

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Cast iron is different from other grill materials in that it is prone to rusting. Just as with a cast iron pan, cast iron barbecue grill grates will rust if not cleaned and seasoned properly.

Cast iron has many benefits including the fact that it gives a great sear and conducts heat very well. There are a few things you can do to clean cast iron grill grates and prevent them from rusting.

The first thing you want to remember to help clean cast iron grates easily is to attend to the grill right after you finish cooking. You’ll want to bake off all the leftover sauce, fats or rubs and food particles that have accumulated on the grates before you begin cleaning grill grates.
Using a stainless steel brush, get into all the nooks and crannies of the grates and remove all the stuff that is left. Any kosher salt or table salt from cooking or rub seasonings can act as an abrasive on the grates and this promotes rust.
Then, take some peanut oil and brush it onto the grates to protect the grates from moisture.

(When you fire up the grill again, you’ll want to burn off that peanut oil, scrape the grates again, and reapply a nice thin coat of peanut oil before your next cook.)

Allow the grill to cool and the ash as well. Clean out the grill with a vacuum or dump the ash. Ash will hold in moisture and humidity and this will start to rust your grates so getting rid of the ashes will help prevent rust.

How To Remove Rust From Cast Iron Grates

If you forget to cover your grill, or you’ve left it alone for a few weeks and you open the cover to find rust on the grates, there are a few things you can do to remove rust before your next grilling session.

1
Try brushing the grates with your wire brush or steel wool and see if the rust comes off. Use a medium grade steel wool and move up to a coarser grade if necessary.

2
If that doesn’t remove all the rust from cast iron grates, use a sandpaper sponge to rub the grates to get down to the bare metal.

3
You can buy naval jelly at the hardware store and this will remove the rust in really serious rust conditions. Make sure you rinse off the naval jelly very well to remove the residue and clean with warm soapy water. Seasoning cast iron grates is the next step.

4
If your grill grates are down to bare metal, you will need to reseason them. This is best done with a heated grill. To season your cast iron grates, apply a thin coat of peanut oil on the grates to reseason the cast iron with a natural bristle brush that won’t melt like a nylon brush will for this step.

If you usually use a coat of vegetable oil, try peanut oil. Peanut oil is a better oil for reseasoning because it resists heat better for the purpose of reseasoning cast iron. Better than vegetable oil, canola oil or another cooking oil.

5
Leave the grill alone for 10 minutes and come back and apply another thin layer of oil.

6
After another hour or two or so, come back and check the grates to see if there is no more metal visible and the surface is now black.

The more you keep applying the oil after every use, the more your cast iron grates will become non-stick.

For storage solutions, you’ll want to keep the grill grates dry so they don’t rust again. Apply oil to the grates and then seal them in a plastic bag, garbage bags work well for this step, so no air can get inside.

Allow your grill to cool completely before putting it away. Your grill needs to have air flow so it doesn’t rust inside it, too. Either keep the lid off or open the vents to allow circulating air to keep the inside dry from condensation as the weather changes.