Chicken stock recipe

Leftover bones and skin from 1 large cooked or raw chicken carcass, or from 2 rotisserie chickens Celery tops and 1 large celery rib, cut into 2-inch segments 1 large unpeeled onion, quartered 1 carrot, cut into 2-inch segments 1 bunch parsley (stems and leaves) Salt, to taste Black pepper, to taste