This item and how to use it

I have found out you can purchase and select skills from the main menu. Go to Play Game > Campaign > Skill Settings.

Note: I know this wasn't here when I first started playing (although saying that the game pretty much starts itself on the first play) and I also only went to the main menu after completing my first chapter, so I don't know if this is a requirement or not.

Items can only be shared in split-screen. In all other modes, items can only be trashed once your character picks them up—not traded, dropped, or cashed in. The function of trashing is to make more space in your inventory, and once it's gone, it's gone forever. Co-op drops are separate and unique, so you can't even save "your" herb for your partner (or vice versa).