Capacity is reached on iPod and cannot manage playlists. It's locked up. Help!

My iPod still plays. It has reached it's capacity and when I plug it into iTunes, my iPod playlists are "faded" and I am unable to make changes to the lists. I want to delete some songs so I can add new ones. I don't want to restore from iTunes, because it looks like my playlist in iTunes has music added that I would never listen to. This is a mess 😟