Much like a cast iron frying pan, well-maintained cast iron grids can provide years of trouble-free use and prevent food from sticking to your grids. To keep your cast iron grids in top-notch condition, heat your grill to about 400°, turn your burners to low and coat your cooking grids with oil using a towel, basting brush or oil sprayer. Frequent reseasoning of your cast iron grids is always recommended.