Originally posted by: rudeguy
Originally posted by: Jeff7
How though? Those things are pretty low power, and I'd expect credit card magnetic strips to have a fairly high magnetic coercivity value.
I have never heard of a cell phone erasing credit card data. I'm not saying that it can't, just that in 11 years of cell phone sales I have never witnessed it happen.
Smaller cell phones may have a neodymium magnet in the earspeaker which can leak a surprising amount of flux - more than enough to damage the strip. Remember it does not have to erase it, just alter it to the point where the reader cannot identify the information.
A compass is the cheapest and most sensitive detector of stray magnetic fields.
Another thing that will destroy cards is a cellphone case with a self closing flap. Those have neo "button" magnets in them. Slide a card within a cm from one and it becomes unreadable. This is a big problem with keycards in the hotel biz as if you get a red light you're not getting in your room!
Once this information is scrambled there is no way to repair it. Well not unless you have equipment you're not supposed to have.
