Elagabalus from Forum.

[Lee S]

I spotted this encrusted coin while browsing the Forum coin store, ( Pic 1 ) and thought " I bet I can do something with that! " , Now while I know that some people like encrustations on there denari, I prefer mine without, so I am very happy with the result!!

  Step one was soaks in ammonia, roughly 15 min apart, with brushes under the tap in between, which removed the green encrustations, ( pic 2 ) then similar timed soaks in phosphoric acid to remove the reddish deposits. with lots of scrubbing with a cut down toothbrush, and some poking with a toothpick in between

  Although the toning is all but gone, the coin is not as shiny in hand, ( I am just crap at photographing silver  ) , and I know it will return, so I am happy to add this coin to my collection ( pic 3 )   

  best wishes,

 Lee S.

[Jochen]

Damned good work, congrats!

Jochen

[Carausius]

Tremendous result! Well done.

[Mayadigger]

Ave!

Well done, Lee. I'm proud of you!

Best,

Kevin

[Mat]

Well done indeed. Didnt know Amonia could be used. Ive just used acetone or lemon juice.

[SC]

I liked it better before.

Just kidding!!  This is one case where it is definitely better now.  Once it re-acquires toning it will be a real gem.

Did you dilute your ammonia?  Or use a specific industrial mix??

Also can you describe what you did with the phosphoric acid - which is definitely not a technique for everyone. 

Shawn

[Lee S]

I used regular cleaning ammonia, I cant remember the percentage, as I have thrown the bottle away, but it was the only one they had on the shelf in the supermarket here in Sweden, ( a very regulated country! ) , so I presume it was not so concentrated , and the phosphoric acid is about 30% ( It is industrial concrete remover.. used for removing concrete splashes from machinery and such.. I tried it out on a couple of low grade silver coins and found it had no harmful effects on the coin ,and it really softens hard stone deposits, and also the iron colored deposits such as seen here!! )
  I just soaked the coin in a little straight out the bottle, I acctualy have no idea how strong the acid is as I have never got any on my skin, and the safety instructions were no longer with the bottle so I am super careful. Also I should add that I temporarily convert my over the stove extractor fan into a fume cupboard ( or go outside on the balcony and shut the door behind me, weather permitting! ) when using the ammonia. Also nasty stuff .
  The green flew off, perhaps 3 soaks, but the brown took longer, perhaps 8 or 9 soaks with probing away at the deposits with a toothpick, and vigorous scrubbing with a cut down tooth brush. I could probably have got the last few flecks off with another couple of soaks, but I was satisfied with the result as it is.

  Any tips on re-toning? While I have no problem giving bronze coins a re-patination, it feels unnecessary on silver, but if I can keep them, ( I have one more denari success story to post later)  in the most conductive environment for toning I will. 

[v-drome]

A word of caution about ammonia.  It dissolves copper, that's why it turns blue, so if a silver coin has a high level of copper in the alloy you can end up with a brittle or porous surface.  Your coin looks very nice.  A friend who was a chemical engineer once gave me a light green liquid, I think it was called drisidol, or something, and it may have been a diluted phosphoric acid.  It worked fairly well on some kinds of corrosion, but not so much on others.

Regards, V-drome