Originally Posted by
ESpen36
It's still a good idea to submit it to the State Dept for official cancellation--doing so will resolve the lost/stolen flag. Don't worry, they'll mail back the cancelled passport to you for posterity. I like to save all cancelled passports because they contain proof of my foreign travels.
Mail it to the DOS. They will cancel it (Final flag) and return it to you. It will most likely have two holes in it when you receive it, but you will still be able to see all of the stamps.