How do you remove a paper poster that is stuck on the wall?

I would try steaming them. >
Try using dishwasher liquid diluted in hot water. Score (make lines with a sharp knife just through the top layer)the paper, then thoroughly wet the area and let sit. It should be able to be peeled off after a few minutes. There are other ways to do this, but this always worked for wall paper, so thought it might work in this instance.