You throw away unidentifiable bones.

[Belhi]

Better yet, the devs could have thrown these items into the quest/key items pouch. I'm not sure why they need to be in standard inventory space.

This is probably so that the materials can be kept if you drop the quest or any spare are kept when the quest is finished. That's my guess.

Also you can sell them for gil. About 1200 gil from memory.