iMessage Question

Can someone verify that Imessage can in fact be killed by a restore? I want to sell my old iP4 and not have the new owner get my iMessages. I have heard a few nightmares and would just assume keep the phone rather than have to change my phone number and apple ID which would be a huge PITA.

Can someone explain the proper way to set up iMessage so that it will be most easily killed in the event of a lost, stolen or sold hand set.

If I set up a separate Apple ID for iMessage would that solve the problem? If so how do I change it from the apple ID I use for iTunes?

Thanks very much!

 

Can you clarify, yes what does. Thanks.