want to put my sim card from my iPhone 4 into family members iPhone 4s. We have both backed up our phones to our computers. don't want his contacts listed on phone while use it just mine. How remove them off iPhone 4s

I want to put my sim card from my iPhone 4 into my husbands iPhone 4s, which he is not using.  We have both backed up our phones on to our own computers.  I don't want his contacts left on the phone while I use it.  How do I remove his info including music, photos etc from the iPhone 4s before I insert my own sim card.