To delete a category for your specs & selections, select "Edit" for an item under that category. From there, you can select the "X" icon next to the category name to delete it.
When you delete a category, any remaining items that are also in that category will need to be reassigned (even on other templates). You will be asked where you want to move them.
If you know that there are no items in that category, then just pick anything in the list. At that point, it won't matter what you choose.