Repolishing vintage plates

[AgNO3]

I was given a handful of old loose plates by a Dag collector friend of mine. They are all not worth keeping for the image and have been pretty much wiped clean by people trying to restore them or the image has been dissolved and the silver heavily tarnished by Thouria dips.
What should be done to prep these plates for polishing? I’ve read in the old manuals that to reuse after mercury development they should be heated to remove amalgam. Would placing it on a guilding stand outdoors and heating it with a alcohol lamp be sufficient, or maybe a Bunsen burner on low? I was also thinking before that I could give it a quick dip in dilute HCl to clean the copper and any scum off the silver.
After that Just buff as normal starting with red rouge on a buffing wheel?

[botticelli1972]

I have done this quite a few times but have never made a "keeper" image. I have never heated them or dipped them, just polished away the old image. It will take a bit more than red rouge to get the old image and tarnish off. The silver sulfide tarnish layer actually consumes/combines with the silver and leaves a very rough surface once it is removed the more tarnish the worse the surface, also old matt marks are often deep and very hard to get rid of. If you polish gently and are not too picky about the matt marks and irregular surface from the tarnish you can often make two or three attempts before you polish through to the copper, assuming the original user got it right on the first try. I have polished old ones multiple times thinking they were still good and then during gilding the thin silver allowed the copper to react with the gold and make orange stains all over the image. One other thing is that the old plates often have the edges bent back and you need to correct the focus to compensate for the plate not being flat. -Larry

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