If you want me to be completely accurate and complete, I can. For the purpose and intent of this discussion, it wasn't necessary for me to mention it isn't always paper. If you take apart mylar or film capacitors, they are indeed film. I *think* (I'm guessing here), in order to achieve the capacity electrolytic capacitors achieve given the same and the surface area, it is necessary to have a material with high dialectic constant in between plates. I think that's why the fibrous structure and gel/fluid.

Electrolytic capacitor has a fibrous structure between foils soaked with electrolytic fluid/gell. If you take apart really old ones, they are actually paper. I haven't taken one apart in the last 30 years so I don't know what they are made of now. Tantalum capacitors are sealed. Regular electrolytic ones aren't. I've seen plenty of them leak, actually. They also do dry up without exploding given long enough time.

If certain equipment comes with an instructions to do certain things, I certainly recommend you follow them. Smaller flash units I have do not have such instructions and neither as many many equipment I have hear that contain electrolytic capacitors. Absence of specific instructions, I don't do anything but use it and fix it or replace it when it breaks.

Anyway, have a nice day.