Tubs and showers are commonly constructed out of fiberglass, a strong, durable material that is non-corrosive and easy to cut and grind. The easiest way to get a fiberglass tub out of the bathroom is to cut it into small sections, which can be done using a jig saw with a fiberglass blade. You can find saws and saw blades at your local hardware store.
Shut the main water supply off, and remove all the fixtures from the bathtub, including the spray nozzle, spout and drain. Disconnect any water or drain pipes connected to the tub.
Remove the caulking from the perimeter of the tub using a small metal scraper. Pry the tub loose with a flat pry bar.
Put on a respirator and safety glasses, and cut the fiberglass tub in half long ways, using a jig saw with a fiberglass blade. Cut each half into three sections, being careful not to cut any pipes that run underneath the tub. If you cannot disconnect the drain from underneath the tub, cut a circle around the drain, staying 1 inch away from the drain. This will allow you to remove the tub around the drain.
Put on safety glasses and pry the sections of tub out one by one, using a flat pry bar. Remove the drain from the cut fiberglass.