Hi John, the "degaussing" technique by Pickering (for former Metron Corp.) is used in the Fluke 7000 reference, which is based on the LTZ1000. This would be an interesting volt-nuts project, to add an degausser circuitry, as it seems that it can be realized easily. On the other hand, I did not find hysteresis effects on a 1ppm level yet on my 2 (3) LTZ1000 references, although my dearest wife has cut off the supply of my double LTZ standard for a few days to save energy. Until then, the box had been running for about 2 years without interruption, and they had been and still are in agreement with the 3458A and the 5442A to the mentioned stability level. Frank