How can I demagnetize a steel shaft. Heat is not an option. The shaft is 0.6 inches diameter and 3 feet long. Note I have seen several devices for sale that seem extremely expensive. Perhaps, if I know what the actual physical process is, then I can just build a device to demagnetize the steel. Also, I have a magnetometer to measure the after affects of the demagnetization process. Thanks in advance for any input.