Find a copper bus bar, or large piece of fairly pure clean copper, you do not want small pieces of copper falling off and contaminating your silver if you cannot find a buss bar from old electrical panel, scrap yard or local electrician, you can use a piece of new copper pipe (not electrically refined like buss bar) will work cutting piece of pipe long wise and flatten out to a sheet of copper, the pipe will have a few more metal contaminate than buss bar but will do the job.
For those who nitric sources and prices is a concern.
Here is something I have been thinking about to save me some nitric acid:
After dissolving silver using diluted nitric acid with a small addition of peroxide (keeping NOx fumes gas low, regenerating the NOx into nitric in solution), (capturing as much NOx fumes generated bubbling into water from the reaction, this will recycle some and help to keep some NOx out of our air), this solution of dissolved silver nitrate will have a small amount of copper, and maybe other metals in solution (possible insoluble values), depending on source material.
Let this silver nitrate solution settle, and decanting any solids from this solution.
I believe if I did not use copper to replace silver at this point, but distilled off the NO2 gas into water with small portion of H2O2 in the receiver vessel, (using the metals already in solution to help distillation reaction, the copper here would help drive out the NO2 gases), making a fairly pure dilute nitric acid in the receiver, getting back a major part of my nitric acid, which can then be concentrated to dissolve more silver (up to 35% or 68% not higher than this, without adding H2SO4). there would be some loss of nitric, but I should get back major portion.
Now left in reaction vessel would be salts of silver crystallizing out, and copper (other base metals in solution, the copper in solution would help to push out the silver crystals, some of this I believe would need some experimentation to determine how concentrated to get this solution and at what point to stop the concentration point,
I think these silver crystals could be dried melted and run in a monitored silver cell (keeping copper in electrolyte within limits even if you have to remove a portion of electrolyte, and replace with concentrated silver nitrate) or better yet re-dissolved these silver and re-crystallized for higher purity, then run in cell.
Just something to think about, I will be doing some experiments later to see how well this Idea works.