I recently acquired a Pentax ME that has been sitting on a shelf for at least twenty years. It may or may not have a partially-exposed roll of Kodak Gold 100 film in it. How can I tell for certain, preferably without damaging either the camera or the film?
(Note that the batteries in the camera are long dead, and the camera has very little manual-operation capability. If I need to replace them to check for the presence of film, be sure to mention it.)