How to delete all of my information on my iphone if the screen doesn't work and it has a passcode?

I have an iphone but dropped it in salt water on beach and its destoryed i got a replacment phone but need to delete all my info before i send it back… But i can't because the screen is destroyed and when i hook it up to my Macbook to hook it up on itunes but it says phone is locked and you have to unlock it to get in it. So how do i delete all my stuff if i can't get in to it Please Help

Take the back of your phone and damage the memory card severly then out it back and tada! No memory just a broken i phone

Try "Restoring" The iPhone?