In searching for a solution for hanging art in my newly renovated classroom, I settled on Grip Strip rails. I purchased three 4 foot rails and three 8 foot rails for the wall in my room. Inside the rail is a series of plastic cylinders. Slide a paper in the rail and it tucks behind the cylinders. Gravity pins the paper inside. To remove, you just gently lift the paper up and forward and it falls out. So far, these things rock! No more poster putty, tack board, etc.