Manually Deleting Contacts
As with life, contacts and address books change with the times. If you find your iPod needs some updating, do like so:
If you dragged dozens of individual vCard files onto the iPod, you can delete individual names by dragging them out of the iPod’s Contacts folder and into your computer’s Trash or Recycle Bin. You can then drag updated entries back onto the iPod from your desktop organizer program.
If you originally exported your address list as one big file, and you’ve made significant changes to it since loading it onto the iPod, you can easily update it. Drag the original file out of the iPod’s Contacts folder to the Trash or Recycle Bin, and then re-export the address list from your desktop program, just as you did the first time. Save or drag the new file into the iPod’s Contacts folder.