Thank you, Norcal. I have not removed any of the bolt in breakers as yet ... but it's good to know that the situation isn't hopeless.
For the curious, this panel is a rather primitive "all in one." That is, the same enclosure has the meter, the main breaker, the panel, and a wire gutter as well. There are separate covers over each section. Panel is NEMA-1. Even though it's a bolt-in panel, it's single phase (240). There are small plastic pieces that cover the area between the breakers.
Age? All I can say is that the circuit directory has yellowed to the point where it's hard to read the black print on it, and the slightest touch will likely cause it to fall apart.
Panel is located inside an old gas station.
