Deleting songs problem

[adampurken2003]

Me and my friend use the same account. Now, I think he added some songs to our main playlist. I just hate some of the songs he added so I thought i would just delete them cause he does'nt really listen to the main playlist often. But I could never find the delete button. I also checked on the songs I've added to the playlist but they could'nt be deleted either. (I checked songs i recently added and songs that have be there for a while). Please help me with this.