As soon as the last burger comes off the grill, brush down the rack with a stiff, long-handled brush and close the lid. The dying coals will continue to burn off anything that remains on the grill, and it will be well seasoned for next time. If you have a gas grill, leave the heat on for a few minutes after brushing. If you brush the rack down after every use when it is still hot, there's no need to remove it for cleaning.