If you neglect cleaning it or simply don't use it for a long time, rust can build up. If rusty grill grates sit around for really long periods of time, the rust can eat into the cast iron so they become unusable, but that takes a long time to happen. In most cases, cleaning cast iron grill grates is rather easy.

How do you stop gas stove grates from rusting?

To prevent rusting of cast iron grates, apply a light coating of cooking oil to the bottom of the grate.

How do you keep cast iron stove grates from rusting?

Seasoning Cast Iron Grates

Well, re-seasoning will help prevent rust from building up on the grates in the future. What is seasoning? Seasoning your cast iron is the process of a type of oil being baked into the very pores of the cast iron at very high temperatures.