Sjouke Burry wrote:

Does anybody know of a way to de-active(blowup) RFID chips?
Can their receiver coils be overloaded?

Given that they have receiver coils, I dare say they could be
overloaded.

This site gives a manufacturer and operating frequency.
http://www.g6phf.co.uk/site/?p=63

The tag you have found is a 125KHz read only LF tag manufactured by a
Swiss company called Sokymat and uses a chip made by EmMarin, part
number EM4102. This has a 40 bit unique number laser written to the chip
at manufacture. The read range is only a few CM, so you won’t oick
anything up from it using ham gear.

It must get power somehow though and I bet you could overvolt that !

http://www.cyntag.com/
Also
http://www.binchip.co.za/
http://www.trossenrobotics.com/store...x?feed=Froogle

http://www.emmicroelectronic.com/web.../EM4102_DS.pdf

Graham