An Atrocious Tasmanian Token

wow keep us posted if you ever find a verdegris covered coin to purge again! wow wow wow! Now all you need to do is post before, and after pics, just like they do in weight loss clinics. You could even photoshop the "after" pic and make it look undamaged, so as to start a business doing it!

Sap, I have a question for you. One of the pennies I soaked in ammonia is now an amazing shade of florescent orange! Almost glow-in-the-dark orange! Did any of yours turn that colour? Is it a possible side effect of the ammonia? I am at a loss to explain how it changed. [:0]

Hey! I've got an idea! I'll list it on ebay as a "rare, scarce, hard to get, one of a kind" and make lots and lots of money. When I've made my fortune, I'll split the profit with you 50/50, what do you think?

Yes, parts of the coin I worked on above have gone orange, in the pits left behind by the verdigris - you can see it in the final scan above. A tip I got from the googled sites on verdigris removal might be worth a try: buffer the ammonia by dissolving some table salt (sodium chloride) in it. I never got around to trying that, because straight ammonia did the job for me.

Is the orange one by any chance a Perth Mint coin? Those often turn up with "natural" bizarre colours (must have been the alloy they used over there) and it wouldn't surprise me in the ammonia treatment enhanced this.

Some tips to keep a coin with verdigris as original-looking as possible:
- If the verdigris spots are only in a small area, don't soak the whole coin - use a cotton swab soaked in the solution to attack the verdigrised area directly.
- Only soak the coins for the minimum time necessary - 20 hours seems quite a long time to me, but I don't know how much time diluted ammonia takes to work.
- Give the coins a thorough wash in water after cleaning, and dry them as quickly and thoroughly as possible.
- Some of the protective oxide layer may well be removed by ammonia, leaving the surface "activated" and prone to sucking up anything nasty from the atmosphere. Try keeping the cleaned coins sealed up in an airtight box, with some silica gel to keep the moisture down.

Again, don't do this en masse to your entire collection - only treat damaged coins. And before you do too much more experimentation, it may be best to keep the treated coins (especially the orange ones!) aside for a couple of weeks to watch for any more nasty "side effects"!

wow that was very interesting, what about the concept of combatting an acid with a base (baking soda), And I have used hot sauce to clean mild cases however it will leave th copper with a pinkish hue,
thanks for sharing SAp.

Cupronickel doesn't verdigrize (I think I just invented a new verb) easily, but it can happen. I don't think it's as "contagious" as it is on bronzes and coppers. It might pay to make sure it's "real verdigris" and not just PVC residue - give it a swish in acetone first. If that doesn't remove the green, then try treating it with something harsher if you like. Any of the suggestions in this thread (or in links you can find in this thread) would be worth a shot.

what other cleaning products would work, and where can I get some?

Andrew

Whoah, timewarp... I'd thought this old thread would've been archived for sure by now...

OK then, it's been over a year now since I looked at this coin; it's been sitting in a mylar flip in my album with the other Tasmanian tokens all this time. So, has time healed the wounds?


Personally, I think it has aged well.

The parts that turned fluorescent orange have, as expected, turned back into a more natural-looking brown colour, very close to the original colouration of the un-verdigrized surfaces - except for inside the pits where the verdigris lay, which have stayed a pale tan colour.

Most importantly, the Green Death has not returned. I am content.