Zappers, especially ours, often leave dark marks on the skin of people who are new to using them. Our zappers also produce this effect in a sort of cyclic fashion if one uses them a lot, which is what we recommend.
The marks can be scrubbed off and are apparently just copper tarnish, produced when the body is acidic. I assume it’s the same sort of mark you see on a cloth when you’re using copper cleaner and of course it’s harmless.
We assume that the cyclic feature is due to the body’s own rhythm of detoxification, which our zappers certainly encourage and assist. When Carol introduced the caduceus/gem coil for the T-Rx these cycles lasted much longer. We tested that notion by switching from T-Rx to Terminator, then back to T-Rx during those cycles and when we used the Terminator the black marks ceased, then resumed the next day when we switched back to the T-Rx.
We mainly use zappers during sleep, which happens to be when the body puts the most effort into restoration and detoxification.
Zappers are not cure-alls, of course, but the subtle-energy components in our zappers seem to powerfully enhance the body’s own ability to heal, defend and restore itself, which is something one can only know from direct personal experience.