Larry, I have dealt with the problem of hollow leaking and causing a
rash in what I believe is a very simple way. I use the boric/alcohol
dip, do the soldering job usually without flux, skip the pickle and
use the ultrasonic instead. Then I towel dry or steam before cleanup
and polish. Back in the ultrasonic then a long dip in plain water,
steam it then finally leave it on top of the steamer allowing the
warmth to evaporate any remaining moisture left inside. The ultrasonic
quickly dissolves the coating we normally remove with pickle.