[Test-Equipment] Shorting plugs for calibrating HP meter?

[DaveC]

The service docs for the HP 34401A DMM say that in order to calibrate 
the zero V. spec, all 4 jacks on the 4-wire input to the meter must 
be shorted together using a "4-wire copper short". It doesn't say 
copper wire, so I envision a piece of copper clad PCB with 4 plugs 
soldered to it.

But all the banana jacks I can find are all nickel-plated (or such).

Ideas? Suggestions?

Thanks,
Dave