Go to any locked treasure chest, face it so that you see the hand on the bottom screen. Go to the character screen. From there, click on your bag and you will see the items that are in the chest on the left side! You can take them and use or sell them like any other item.
Get through the game past the Cyclops and into the Trophy Room where you can find the hidden door to meet Oliphant. Talk with him until he tells you that you have not found the "Book of Right." Select, "We Begin Again" and you will get a major boost to experience. Leave his room to go back to the Trophy Room and either die or just reload.