does anyone believe in it? or have tried parts with this treatment? (pickups and stuff) Bill at callaham guitars does it to pretty much every part that a current will flow through. I'm not sure i believe it would make a difference, but some people have some strong opinions about it. and i want to know yours. here is Bill callahams explanation of the whole deal regarding pickups. http://www.callahamguitars.com/ use the menu on the left to go to "cryo & pickups"