Grease four baking sheets with 2 tablespoons butter; set aside. , In a large heavy saucepan, combine milk, sugars, corn syrup, salt and remaining 1 cup butter. Bring to a boil, stirring frequently. Cook over medium heat until a candy thermometer reads 238° (soft-ball stage), stirring occasionally. , Remove from the heat. Stir in pecans and vanilla. Drop by tablespoonfuls onto prepared baking sheets. Let stand until set. , Drizzle melted candy coating over clusters; refrigerate for 10 minutes or until set. Store in airtight containers.