Pull out any leaves of fat from the body cavity of the duck.
Sprinkle cavity with salt.
Place duck in roasting pan.
Put giblets and neck in the second pan.
Roast duck and giblets in hot (425°) oven 30 minutes.
Remove pan with giblets.
Reduce oven heat to moderate (325°) and roast duck one hour longer, pouring ofl’ fat as it accumulates in the pan.
Meanwhile, add water, onion, and ½ teaspoon salt to giblets and neck and simmer about 45 minutes.
To prepare orange peel, cut a thin slice, orange portion only, from orange, and cut into very thin slivers. Cover generously with cold water and boil 10 minutes.
Drain off water and reserve peel.
Combine sugar and vinegar in a small saucepan and boil 3 minutes.
Add ¾ cup stock from giblets, orange juice, ½ teaspoon salt, cloves, and catsup.
Simmer about 5 minutes.
Blend cornstarch with sherry and stir into sauce.
Cook and stir until clear and thickened.
Strain spices from the sauce, add slivered orange peel.
Pass sauce separately to be spooned over servings of duck.