It is well known that the only way to kill a zombie is to attack its head. However, the works of Robert Kirkman tell us that it is not sufficient to chop the head off. Instead, it is necessary to inflict severe brain damage either through the use of a blunt instrument like a spade or by using a gun. An axe can also be used, although illustrations in many works, including Kirkman’s show that the axe needs to penetrate deep into the cranial cavity to stop the zombie.
It is worth noting that zombies freeze more easily than living creatures. This can be used as a way of stopping them in very cold conditions. Please be aware that they will continue as before when they finally thaw.
The most important thing to remember when confronted with the undead is to keep your wits about you, this will be your greatest weapon.