We did this one year when I was a room mother. Think it was for first grade. Kind of a take off on pin the tail on the donkey. We drew a great big witch with a huge nose and taped it to the blackboard.
We then gave each kid a piece of gum. And, had them chew it. Then we blindfolded each kid turned them around a few times and told them to give the witch warts.
They had an absolute blast doing it. Not often you get to take gum out of your mouth and stick it somewhere.