This is just a bug report. I did a search for it, and couldn't find anything.

After the guy in the Bannered Mare in Whiterun got me drunk and I woke up in the Temple in Rift, I opted to pay off the fines I incurred instead of just picking up the mess. But after I finished talking to the priestess, I picked up the Giant's Toe that was lying around, because they're handy ingredients, and now I can't get rid of it. I can't eat it, drop it, sell it, or use it in Alchemy, because it says it's a quest item. I tried talking to the priestess, but she has no options for accepting it back. And now, whenever I pick up another Giant's Toe, it becomes part of that stack, and I can't use any of them.

I still have not finished the quest ("A Night to Remember"), so I'm hoping that once I do the whole thing, I can get rid of it, but this definitely seems to be a bug.