You may:
clone out incidental power lines, twigs, dust specks, stray hairs, and similar minor imperfections within any capture used.
BUT
You may not:
use ANY editing tool to move, remove or duplicate any element of your photograph that would change a typical viewer’s description of the photograph (aside from color or crop), even if the tool is otherwise legal, and regardless of whether you intended the change when the photograph was taken.
So, if a small, very thin wire/string/stick was used to help position an element of the image, would that be treated as "incidental" and "minor", and could it legally be cloned out or otherwise removed without getting a DQ?
I'd like to piggy back, because I too had a very similar question, but not enough time to consult the site counsel before the challenge deadline.
In my image:
I had a small table in my living room that ended up getting exposed along with the ceiling. I cropped the ceiling out, and just to err on the side of caution, I cropped the table out as well. I liked the composition more vertical, would I have been in the safe to clone out the exposed edge of the table?
IMHO its always safer to burn it to a crisp, so there is just a whisper of the element you don't like, when you are not sure if it would hit the major element rule.