I'm sorry, but the cleaning techniques in Egypt leave a lot to be desired. You are dealing with ancient metals that have been corroding, crystallizing, or may have other serious issues after 2,000 or more years under ground. Cleaning it like you would clean a common item of jewelry someone bought from the store 4 or 5 years ago, just seems so wrong. I know they literally have thousands of coins they process every year due to all ancient activity in Egypt, and can afford to damage or destroy a few hundred with no problem (and I bet they have too), but man, that was rough to watch.
I liked the documentary, but the whizzing and electrolysis etc had me cringing!! I understand that this cleaning/conservation technique is typically utilized at Museums....although I hope in a far more controlled and precise manner. And I wonder how many coins we all have in our collections that have been 'cleaned' in such a manner.
More now than once upon a time. Even some of the big dealers seem to prefer coins that have been brightly cleaned. You saw fewer like that in old sales. I prefer sales where not every coin is the same white color.
Toned silver is pretty. As long as it doesn't get so dark and so thick that you can't see or appreciate some of the design well, I'd say leave it alone. And even in that situation, a light and very gentle cleaning is best, preferably one that doesn't remove most of the toning.
