Here's a recent find that might do well in the "ugliest roll find" competition for silver-clad
Kennedy halves. The corrosion was pretty severe. With basically nothing to lose I gave it a hot vinegar soak for a few minutes. It's still ugly but maybe not quite as bad.
When these coins have milder cases of green verdigris the vinegar treatment can often completely remove the corrosion without creating any new problems, at least as far as I can tell. This one was just too far gone....
Before chemical peel:


And afterwards:

