Using my iPhone as just an music device and not a phone?

I don't use my iPhone 4s as a cell phone anymore, what is the best way for me to clear everything except the software needed for music?

You can't. The phone function is there no matter what.

You can't do it the iphone will just stay an iphone unless you bring it to apple samsung etc so you can get phone off and just use the music thing

Pull your sim card and it's no longer a phone. The basic apps will stay though.

Why?