Grilled Sweet Corn

1A. FOR A CHARCOAL GRILL: Open bottom vent completely. Light large chimney starter three-quarters filled with charcoal briquettes (4-1⁄2 quarts). When top coals are partially covered with ash, pour evenly over grill. Set cooking grate in place, cover, and open lid vent completely. Heat grill until hot, about 5 minutes.
1B. FOR A GAS GRILL: Turn all burners to high, cover, and heat grill until hot, about 15 minutes. Turn all burners to medium-high.
2. Meanwhile, remove all but innermost layer of husk from each ear of corn (kernels will be covered by, but visible through, last husk layer). Use scissors to snip off long silk ends at tips of ears.
3. Place corn on grill and cook until kernels have left dark outlines in husk and husks are charred and beginning to peel away at tip to expose some kernels, 8 to 10 minutes, turning every 2 minutes. Transfer ears to serving platter and remove and discard charred husks and silk. Season corn with butter, salt, and pepper to taste and serve.