[ChrisW]

To get rid or duplicates and/or wrong parts, you'd have to long press one, tap each one you want to delete then tap "Delete" in the action bar at the top of the screen.

Mike

@Mike
this can be a quite annoying task, especially if the metadata for the imported songs is not sufficient to distinguish old from new. In this case one has to open all songs and see which one is the old.

@all
Thank you for your comments an ideas how to deal with it. 

Best regards
Christian