thinking about electrolytes and conductivity

In this lab, first we got all of our materials, like the pennies, salt, water, vinegar, matte paper, sandpaper, and LED lights. Then, we started rubbing the copper of the pennies for 4/5 of the pennies on the sandpaper, and then we soaked the matte paper in a solution with vinegar, salt and water. After this, then we put the matte paper, and the pennies together with the LED light. We tried using other LED lights, with different colors, and tried re-doing the solution, but none of them worked. 

The reason all this happens because it's like a battery. Because of the positive and negative sides, it creates a battery-like product. Unfortunately, ours didn't work. When metals are connected to  electrodes, and are connected to a wire, the electrons move from one penny to the other, creating an electric current. The reason our didn't work could have possibly been because we used a 1982 penny, which would have not been a post-1982 penny. Also, our solution could've been wrong because we could've used too much or little water, salt or vinegar. The mattepaper soaked in the electrolyte-like product due to the acids, created an electrolyte between the two pennies. Alessandro Volta, who created the first battery, which is why this is called a voltaic pile. 

Here are out pictures of the lab. First, here's a picture of the pennies on the sandpaper, then there's a picture of the final penny battery. As you can see in the bottom two pictures, the LED light did not turn on.