Light 1 chimney full of charcoal. When all charcoal is lit and covered with gray ash, pour out and arrange coals on one side of charcoal grate. Set cooking grate in place, cover grill, and allow to preheat for 5 minutes. Alternatively, set half the burners on a gas grill to the highest heat setting, cover, and preheat for 10 minutes. Clean and oil grilling grate. Place corn directly over hot side of grill and cook, turning occasionally, until charred on all sides and fully tender, about 10 minutes total. Remove corn from grill and allow to rest for 2 minutes. Roll in butter, sprinkle with salt, and serve immediately.
