In a small microwave-safe bowl, place butter and garlic. Heat on high until mixture begins to bubble, about 1 minute. Stir in vinegar. Set aside.
Preheat grill to very high heat (450°).
On a large rimmed baking sheet, place oysters in shell, making shells as level as possible. In a small bowl, stir together salt and peppers; sprinkle evenly onto oysters. Spoon butter mixture on top.
Carefully place oysters on grate at center of grill. Grill, uncovered, until oyster edges curl, 5 to 6 minutes. Transfer to a serving platter. Serve with lemon wedges. Garnish with chives, if desired.
Notes
INDOOR ALTERNTIVE
Preheat oven to broil, placing oven rack 3 to 4 inches from heat source. Arrange oysters in shell on a foil-lined rimmed baking sheet. Prepare oysters as indicated. Broil until oyster edges curl, 3 to 4 minutes. Serve as directed.
Recipe by Louisiana Cookin' at https://louisianacookin.com/charbroiled-oysters-garlic-butter-sauce/