

Low-Tech Fixes for High-Tech Problems  - taylan
http://www.nytimes.com/2009/02/19/technology/personaltech/19basics.html?pagewanted=all

======
ieatpaste
If you're wondering about the credit card-bag trick, here's a basic
explanation: After extended use, the oxide (written information) will
"smear"and produce lower-level mag fields. These will give a false value and
effectively not be approved by the checksum. By increasing the distance (via
bag, tape, etc) between the read head and the strip, the sensitivity falls and
only the original data (higher-level mag fields) will be read.

[http://www.newscientist.com/article/mg19225752.500-money-
bag...](http://www.newscientist.com/article/mg19225752.500-money-bags.html)

