If The Skimmer is External

And a person is POSITIVE the clamp on device is a skimmer...

Passing two ounces of N52 grade Neodymium magnet near it positively destroys the device, magnetizes the ferrous structure and it is then fit solely for chatarra,

But powerful magnetics can pose a hazard both to a legitimate ATM and to any nearby credit cards. I have destroyed three of these devices in the last five years. The banks were closed and the one grocery store refused to put the HSBC ATM out of service at 9:30PM. With two of the machines, they continued to function as normal with customers, and the third I did not keep track of.

Zihua Rob's way is better. Because it does not risk the machine from misuse of the super magnet.