I've busted up a buch of that old cast iron stuff. The reason you break them up is because there's no other way to get them out. Especially if they're on the frikkin' second floor. Most were installed before the walls were put up. Now they won't even fit in the hallways or maneuver around corners.
DUmmies don't understand the concept of a bid job. If you try to save such boat anchors, you'll lose your ass! They're not worth trying to work them into the budget, even if they are antiques, in most cases.