thinking about electrolytes and conductivity

Sadly there was no reaction during the experiment with our pennies. However, I am still able to identify which electrolytes were present. To begin with, since all ionic compounds are electrolytes we know that vinegar (acetic acid) was an electrolyte. We also know that the sodium in the salt was an electrolyte. Lastly, we know that the wet cut up cardboard were also electrolytes but I do not know if the electrolytes came from the solution are the paper itself.

pennies after being rubbed with sandpaper

cardboard before being cut and dipped

solution after being mixed with salt and vinegar

solution after adding pennies

pennies with cardboard and led attached

We got 2 volts from the experiment.