Wait is it in the character inventory or the storage? You keep saying both. 
I assume it's in the storage. It's still in w00_tCharacter..tItem but when it's in storage the nOwnerNo is set to your accounts nEMID/nUserNo rather than nCharNo. I think that the nStorageType is set to 6 rather than 8 when the item is in storage. Instead of finding that particular item, it would be faster to just remove that item from every character/account with a query.
Code:
DELETE FROM w00_tCharacter..tItem WHERE nItemID = '250';
Change 250 with your bugged item's ItemID from ItemInfo.shn