You don't need50/50 vinegar or washing soda either. All that is needed is just enough vinegar (or for copper, ammonia) to make the water a conductive solution. The electrolysis proceeds as a reverse electroplating, and deposits the fouling on the rod as elemental lead or copper. I used it on a S&W 1917 that I( thought had a ruined barrel. It removed enough lead to show the rifling, and when retreated for copper, left me with a shootable (yes it was still pitted) barrel. You need to be cautious about spilling vinegar solution on blued surfaces - it will strip blueing very quickly.

The process should be done with a low voltage (ca. 5 volts) and a low amperage ( no more than 100 milliamps ). Be patient, expect to spend several hours and several changes of fluid. And when the process slows down, remove the rod and wipe off the deposits and then put it back in.

John