I think it's best to use gold solder when soldering silver to gold
and this may help. I also have great luck with Wite Out Plus by Bic.
I use it to keep solder from flowing where I don't want it, and it
also helps me to keep gold from "running" when soldering to silver.
Might be worth a try. I have suggested it to others who say they
don't want to mess up their pickle. It does form a "silt" at the
bottom of my pickle but I can't tell it interferes with cleaning.
J. S. Ellington