Ghost tracks - how to remove?

I have been using iTunes happily for some time now but in recent months - well since I swopped to a Mac actually - I seem to have acquired a large number of ghost tracks. These are all copies of existing tracks, the existing tracks work happily, the ghosts don't. They are only visible in itunes, on my device, music and there they are. They leave two symbols - either the ! in a circle or the dotted line circle (see image)

Now I know what the ! in a circle is these tracks can be made to work but the dotted circle doesn't work at all no right click! no left click! nofink!

The tracks are available to play as single items in the right playlists on my iPhone after the sync and the tracks are in my normal library - they only appear in the "on my device" section of iTunes and it is driving me nuts!

Any ideas?

Thanks