Mix salt, brown sugar, chili sauce, and vinegar together. Pour over meat and let stand overnight in the refrigerator. Preheat oven to 325 degrees. Place the meat in an ovenproof casserole, pouring marinade over meat. Cover with the celery leaves, onions, and carrots and water. Cover and bake for about 2 hours, basting often with marinade. Remove cover for 1 more hour. (Allow approximately 1/2 hour per pound for roasting.) This dish is best prepared in advance so that fat can be easily skimmed from the surface. When ready to serve, slice and reheat in the strained pan marinade