Correction

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

In my rambling post on electroplating radon daughters I may have
said the post would need to be positive relative to nearby surroundings.
It would need to be negative to attract and plate radon daughters.

Also, a trick that was used to reduce contamination from loose
radium sources was to connect a negative electrode of a 100 volt
battery to an insulated plug in the shield.  The rest of the shield
was connected to the positive electrode.  Daughters were then plated on
the plug reducing long lived contamination of nearby objects.

Dale