It's so frustrating when you're trying to remove a nail when the head has snapped off. Here’s a simple and effective way to remove the offending nail.
Clamp the vice grips onto the shank of the nail. Depending on how long the nail is, you may have to re-adjust the vice grips a few times.
Use your hammer as you’d normally use it. The vice grips provide added leverage for the hammer, making it easier to remove the nail.