Deleting unused items in S2k has always been an issue and in general S2k does NOT allow this on a mass basis due to the fact that even though items are now unused they are still in the system and cannot be deleted.
Currently if an item is not used, not sold AND never purchased at all in the system, we have a way to delete them. You can view these items in the price book section on the first page and review this list as shown below:
If you are comfortable deleting this list then go to the following section: