Unchecked songs from my iTunes library sync to my iPod
I have an iPod touch that has 314.9 MB of space left. I have less songs than I had on my old iPod, and same goes for my iTunes library. It's version is 8.4. A lot of the space is being taken up by "Other," which I do not know how to get rid of. I got a new MacBook Pro a few months ago, and I synced it up with my iPod, but songs that I have unchecked in my iTunes library keep syncing onto my iPod. I also have songs I never downloaded on my iPod, and are not my computer (these may be another family member's). How do I delete and not sync songs I do not want since they cannot be deleted by the standard sliding and pressing delete on the song?
I've considered restoring my iPod, but I'm afraid I will lose songs I want that aren't on my computer, and lose app data.
iPod touch, iOS 8.4