Bottle messages

 is a paper note that can be found and obtained within the Commonwealth, in Fallout 4.

Behind the scenes
The message contained within Bottle message #5 - Difficult to kill is a direct quote of John McClane in the motion picture Die hard; specifically the scene when he climbs through the air vents. Furthermore the scene it leads to is a reference to the movie; the skeleton in the bathtub has a teddy bear, a pack of duct tape and a gold plated flip lighter. These items are used prominently in the movie.