never done it myself, but I stumbled accross this cache just yesterday out in Dawson Forest..
I was kinda scared opening it. I figured it was a geocache but you never know..
The litte camera inside didn't work, so I just left a message on the notepad provided. It had a few flashlights and some batteries. All of which looked to be in about the same condition as the camera. So, i didn't take anything, just closed it back up and left it where i found it.