Circumcision is a medical procedure that removes some or all of the skin covering the head of a boy's penis. Taking away this skin can help a boy stay healthy and keep his penis clean. To do the procedure, a doctor or a nurse will put a special clamp on the penis and use a sharp tool to remove the extra skin. Although it is usually done when a boy is very young, it can sometimes be done when a boy is older. After the procedure, the doctor or nurse will put some medicine on the penis to help it heal.