With this new system you no longer need to keep unwanted power scrolls but you can make something useful out of them; you can go to the Center Mall (Public Gate / Vendors / Center Mall) and double-click the white stone so you can exchange your power scrolls for special ps tokens. The tokens can be used to purchase a power scroll you actually need! There are a number of options to choose from in this system, including randomization of a power scroll for a hefty price.