How to restore iphone on iTunes?

My daughter broke my phone so I'm getting a new one sent to me because of
My warranty but I have to send my old on to them but they won't take it if it's not wiped. But when I put it into my computer it says I have to put in the password other wise I can't wipe it but I can't put the password in because it's broken. Is there anyway around that because I need to restore it without unlocking the screen?

With find my iphone you can also remotely wipe your phone, sign on to http://www.icloud.com/...icloud.com for that