officially there is no workaround for this glitch for PS3 or XBOX 360 users. (Only for PC users via console)
That's from wiki:
For the three quests involving the retrieval of instruments, the script for removal of the quest items from one's inventory at the completion of the quest is bugged.
As such, these items will permanently be in your inventory (they're flagged as Quest items).
Beside that the only think you can try is this:
Make a backup from your saves (to be sure) !!!
If you are on 1.9 patch (and i think your are...) and if you haven't started so far any of the DLC's do this:
Delete your main game. Re-install it again but without any patch. (so, no 1.9 patch)
Load your save and maybe the game will let you remove or even store your item somewhere.
OR
- When you level up, if you select stamina, you will increase your carry weight by 5 pounds.
- Also for 3 perk points, you can get the Extra Pockets perk in the Pickpocket tree which increases your carrying capacity by 100. This perk does require 50 skill in Pickpocket.
- The Light Armor and Heavy armor trees have perks that let your armor become weightless.
- Weightless Heavy Armor costs 4 perks, and needs 70 skill.
- Weightless Light Armor costs 3 perks, and 50 skill.
- There are pieces of armor with the 'Fortify Carry Weight' enchantment
- There are 6 alchemical ingredients *** with the 'Fortify Carry Weight' property and potions of the same name.
- Finally, if you can find it, the Steed Stone *** will also increase how much you can carry.
*** http://elderscrolls.wikia.com/wiki/Fortify_Carry_Weight
*** http://elderscrolls.wikia.com/wiki/The_Steed_Stone_%28Skyrim%29