Thank you all for your replies.
Cynthia, I will add the steps you suggested to my work process.
The Argentium rings did not come in contact with fine silver. The
only possible contamination would have been from copper or from
sterling silver. I am using a separate soldering pad for the
Argentium, but have not yet added a second set of polishing
Will the Argentium rings that I have not oven hardened/tarnish
protected in any way (hardness, tarnish resistance) be inferior to
regular sterling silver rings?
I am getting more concerned about the people who do not react to
regular sterling silver, but have issues with the Argentium silver.
Another customer purchased rings for herself and her boyfriend. Both
get black stains on their skin. The photo she sent shows lots of
black on the finger, none on the ring. I have sent them regular
sterling silver rings to test and both have no problems with those.
I am concerned that some of my buyers might not let me know if they
have problems with the Argentium and assume that I have sold them
inferior metal. Since Jason, Brenda and Vera have also encountered
problems, I am guessing that those problems might have to be expected
with a certain probability.
Is there any way to find out what percentage of the population may
have those issues?