Hello all and my 1st post. I followed this thread in the Region 8 newsletter and here also and just got around to posting about it. Having spent the last 10-15 years experimenting with coin restoration (i.e.: verdigris removal, carbon spot removal, ground find corrosion, etc) I have managed to destroy a few coins and learn quite a bit about re-toning etc. I will say, in my experience, that no "magic bullet" exists for re-toning of copper for multiple reasons. Copper is very reactive and prone to corrosion and since the coins we refer to are not pure copper but actually alloys of a variety of metals, which varied from year to year as the mint experimented with durability and other issues regarding the dies used, it is difficult to say that one single solution will work magic on all coins. I will say that my experimenting led me to a fascinating side hobby involving ancient uncleaned Roman coins and a lot of very useful knowledge on cleaning, corrosion removal, re-patination and restoration which has served me well with the old coppers that we all love. I have used all sorts of chemical concoctions in my ancient coin experiments to re-tone copper and have had great and not so great results in the process. My advice is to tread very delicately in the application of anything to a coin which is near and dear to you or valuable as the possibility of making a bad situation worse always exists when tampering with copper. I have a local coin shop owner who always gives me a pile of old copper and some silver coins with corrosion or coloration issues to see if I can fix them up for him for resale. He has trusted me with mint state pennies to remove carbon spotting or green verdigris and I am always very nervous to screw up his inventory with my attempts to clean em up for him. He always marks the coins as re-toned so as not to deceive anyone. SO in closing on this long winded post, a quick rundown of some of the "tools of the trade" so to speak: homemade toning agent similar to Dellars, various homemade tools
(from small brass rods to wooden picks and almost anything in between) to remove verdigris deposits (steady hands required), acetone or denatured alcohol for dirt and other assorted debris removal, and even some more drastic items which I won't get into in this post. Almost any tampering will change the natural toning of the copper and it is nearly impossible to get that warm medium brown tone that only time can impart. Restoring the toning on a coin is a lot like the process when a painter tries to re-create a scene on canvas. More than one attempt is sometimes necessary to achieve the expected result and sometimes the stubborn old copper coin refuses to cooperate and just doesn't look too good when finished. When I get some free time, I will try to post some pics of toned copper for you all to judge. Feel free to ask away with questions, but as always, experience taught me the most about the subject and I have literally messed with thousands of ancient Roman coins over the past 15 years to get to this point in re-toning.