In a medium bowl, whisk together ketchup, sugar, Worcestershire, and vinegar; season with salt and pepper. Set aside 1 cup sauce for tossing raw chicken; use rest for baked chicken.
Preheat oven to 450 degrees, with racks in upper and lower thirds; line two rimmed baking sheets with aluminum foil.
Divide drumettes between baking sheets, and toss with reserved 1 cup sauce.
Bake chicken until opaque throughout, 30 to 35 minutes, rotating sheets and tossing chicken halfway through. Toss baked drumettes with 1/2 cup sauce, and serve with remaining sauce on the side.
Chicken drumettes are actually part of the chicken wing -- just the right size for kids to nibble on. To store, refrigerate, up to 2 weeks.