When you torch it does it get rid of the nickel base too? Yes it
all evaporates off the silver.
Not likely. Neither does the gold. Think about it. If you melt just
a bit of gold, does it actually evaporate? No. Neither does nickle.
Instead, both dissipate INTO the silver. They aren’t being removed
from the silver, just diffused into the mass. The surface no longer
looks plated, but the plating metals are not removed. They still
contaminate the silver. If you wish to remove it, you have to either
electrostrip it, etch it off via acids or other such, or mechanically
remove it by abrasives (tumbling with abrasives, for example)
Also, after re-reading my last post, I think there may be a clue
why they won't take it. I use an acid based solution, but some
solutions are cyanide based. Burning off cyanide doesn't sound like
a wise idea, and it may be the issue.
Huh? Did you think the plating solutions remains in the electroplated
layer? Neither your acid based solution or the cyanide solution leave
remnants of their chemistry in the plated surface unless you’re doing
something seriously wrong in your plating process and trapping
solution in some sort of hollow pockets or cavities (unlikely).
You’re not burning off either chlorides or cyanides. And if you were,
incineration happens to be one of the few process that actually DOES
destroy cyanides relatively safely (if hot enough…)