Please, never ever use a zapper that connects to the AC wall power when trying the following. It could be the last thing that you ever do.
One of the best methods for zapping that I have found is to place the positive electrodes ( I use paddles and pads ) into a bath tub full of water with plenty of Sea Salt ( 1/4 cup ) and Epsom Salt ( 2 - 4 TBSP ), then submersing ( mostly ) with one hand holding the ( relative ) negative electrode out of the water.
This appears to provide a universal pathway through almost all parts of the body.
Feedback that I have received from those with Morgellons and some other skin conditions, is that it works well. Some have also added a little borax to the water. Caution is recommended.