Baleful Gem and Milgaro's Spike quest item bugs

Hello,

I'm starting to get a build up of quest items in my inventory and its difficult to actually pick items up. I can't seem to get rid of Baleful Gem and Milgaro's Spike even though I've tried talking to the NPC's multiple times. Is there anyway to drop or stash these items? Because I can't figure it out.

You need them in later quests.