Electrolysis.
The hostess discovered an interesting thing. In general, with the electrolysis of salt with a zinc anode, he wipes everything with sludge. But if you push a nauseous zinc anode on half a cone into the solution, then the output through the current of destruction of the anode is much smaller. And you can do more electrolysis. More alkali and zinc chloride
Perhaps the same chip will roll with a graphite anode. If you insert it on half cones, then chlorine will be released little, but you can get hydrochloric acid