Refines

Refines or trash items are the most wanted items when refining other ingame items and some of those 'trash items' are sometimes assigned in combinations to gain strength.

Why are trash items so important?
Refines or trash items most likely carry the whole economy in the game, thus becoming very important. Also because some refines / trash items have a high potential because they are needed to refine (obviously to the nickname it has been given).