Hi,

I'm left with some items from the past Carpo Harvest Kami, and I'm not sure what to do with them. Are they still usefull for something? Can they become usefull in future Quests? 

I wouldn't like to see them go to waste as my shells and ink are currently (I have tons of those, just sitting there on the shelf).

To the best of my knowledge quest items aren't usable in multiple quests. Fortunately quest item don't actually take up inventory spots.