How to take all songs off my iPhone 4s?

I'm trying to start anew with my music library, so I decided to take off all the songs currently on my phone. I connected it to my computer, went into itunes, and unchecked "sync music" expecting it to totally wipe my music library on my phone. It took off most everything, except for 20 songs that I can't get rid of! I've tried every way of deleting them from itunes, and there doesn't seem to be a way to get rid of them from the phone itself. It's bugging me to no end, especially considering I don't want most of those 20 songs.

That sucks