Light one chimney full of charcoal. When all the charcoal is lit and covered with gray ash, pour out and spread the coals evenly over entire surface of coal grate. Set cooking grate in place, cover gill and allow to preheat for 5 minutes. Clean and oil the grilling grate. Place the foiled corn on the grill and cook until tender and slightly charred, about 20 minutes, turning 4 times during cooking. Remove from the grill and let cool for 3 to 5 minutes.