The cotton padding beneath is hard to dry and may cause your skin to develop a rash or infection. Doctors sometimes make tiny cuts in the side of a cast to allow room for possible swelling. Your cast may also develop cracks on its own if it's been hit or crushed, has a weak spot, or if your skin begins to swell underneath. New cracks should be reported to a parent immediately and then examined by your doctor. Also, if you notice that your cast is causing your fingers or toes to turn purple or blue, it may be too tight and your doctor may have to change it.
Doctors use a special saw with a dull, round blade that vibrates up and down.
The vibration is strong enough to break apart the fiberglass or plaster, but it can't hurt your skin. But a word of warning. The saw can be so loud, some kids think it sounds just like a vacuum cleaner. Just remember that it will sound much worse than it will feel. Sometimes your doctor will let you keep your cast as a souvenir - all you have to do is ask.