First, face a locked treasure chest so that the hand appears on the touchscreen, then go to the character screen by selecting the stick figure at the bottom right. Tap on your bag and the items that are in the chest will appear on the left side of the screen. Take them without picking the lock.
When you get to the Cyclops and into the Trophy Room, go through the hidden door to meet Oliphant. He'll tell you you have not found the "Book of Right." Choose "We Begin Again" and you will earn experience bonus. Return to the Trophy Room and die or reload your game. You can talk to Oliphant again to receive the Experience boost -- you can repeat this as many times as you want.