It sounds too cheap, and simple to work, but I had really good luck killing Ascaris in the liver from tapping just on the 9 volt battery.
Just put a square of wet paper towel on the end of the index finger's on each hand. Hold one index finger on one of the posts of the battery, while you start tapping with the other one. Switch if your fingers get tired.
The Hulda Clark rounds 7-20-7-20-7
Alot of times I would just keep going with the last one, and not stop at 7.
The nice thing about the simple battery tapping, is how easy it is to take a 9 volt battery with you anyplace.
The other one that worked very well, was what Hulda Clark calls the Simple Zapper. Putting alligator clips on the ends of two pieces of electronic wire (4 alligator clips, 2 wires), hooking each wire to the battery posts, and hooking the other ends of each wires to copper pipes for handles (wrapped in wet paper towel)..hold one pipe, and start tapping on the other with the base of the fingers.
You can switch hands when you get tired..but again doing the rounds.
I would have to look up the PDF book of Hulda Clark 's again because I loaned out my book, but I think the simple tapping/zapping like that is 5 hz? Parazapper can verify that.