I converted many media files in iTunes to be suited to iPod. Now I have all the selected files along with the converted files (unselected).
I now want to invert selection so I can easily delete all the old files. How do I do this?
If they have different media types:
If they have the same media type:
You can always sort by the check marks by clicking on the column header. Once the checked songs and un-checked songs are grouped together, you can highlight the group you want to delete (click the first of that group then shift-click the last of that group) and hit the delete key.
This also moves the files to the recycle bin, so you can easily undo it if you get it wrong the first time.