cast iron tub

Probably starting to sound repetitive, but these tubs are very heavy. If it is a built in tub and has no real value, definitely break it up with a sledge hammer. It will break easily into manageable pieces. If it is a vintage claw foot, well you might want to enlist two or three buddies. If she is having it replaced, it is usually the plumber's job to remove it and they would be responsible fro getting it downstairs. Of course, the customer's plan may be to save some money. So just be careful...