As title says, I suggest adding NPC exchanging carapace box of one kind to another. So If someone got trolled like me, and got carapace shoulder box after obtaining bioluminescent shoulder skin, he would be able to exchange it for box containing other kind of carapace skin. For example gloves.
Drop rate of carapace boxes is so low that it should be worth more thanfew silver coins when sold to NPC…
Or make it sellable on TP