how do you get those copper-silver medieval coins to look good?

[orm25]

Hi,
I have purchased these Hungarian coins of ebay. Some of them are silver but when i was cleaning them i realised that they have changed more of a orange copper color.
I have like 5 of the same coins that are silver-copper alloy and they're not all silver colored apart from 1. I have had some outstanding results with vinegar with a coin that looked like
nothing turned to a coin with lots of details.

 

[Iron Patch]

You will not get that result unless the coin still retains a lot of the surface silver pre cleaning.

 

[loneranger23]

Best way to clean real silver in the uk is to use some tin foil put the coin inside the foil spit on it and press the coin between the foil and it should start to gey warm then rub it gently between the foil I know the method aound unorthadox but it works a treat and tell you if it silver or not because if its not silver it wont warm up in the foil and spit

 

[mindcrime1988]

I'm sure a lot of folks would agree with me when I say use nothing more than soapy water & a soft brush. If you really cherish these coins, then I would not attempt in cleaning them anymore than this. If you are willing to take the risk and possibly ruin the coins, there are several cleaning methods out there but none are going to make your coins look new. I wouldn't chance it!

 

[Generic_Lad]

I don't think that these Hungarian denars are very high grade silver, and I think that often the alloy was improperly mixed. Those coins with higher grade silver are likely to be much better looking, while those with more copper have likely corroded. It looks like your coins on the left have a lot more copper in them than the one on the right, thus it looks "better". Since most of these hammered coins are dug coins, the silver won't be affected by the ground moisture as much as the base metal ones.

Sometimes these lower-grade silver coins have been plated with silver so that they look better and look like higher-grade silver and so those with full silvering will look better than a coin which had its plating worn or flecked off. Although I'm not sure if these coins were, there seems to be a lot for sale, but comparatively very little information on them.

For example, here's a British (Edward I) sterling penny:



Which is in fairly good preservation because of its high silver content.



This, on the other hand is a Henry VIII testoon (shilling) made out of debased (about 1/3 silver, 2/3 copper) and even though its nearly 400 years younger than the Edward I above, it is in worse condition because the elements attack copper more readily than they do silver, so the coin is partially porous and has a worse colour.

 

[huntsman53]

Clean them with Acetone! Never use vinegar, especially on old Medieval Silver coins as it can pit them and since most contain some amounts of copper, it can bring the Copper color to the surface of the coin.


Frank

 

[Silver Searcher]

I don't think that these Hungarian denars are very high grade silver, and I think that often the alloy was improperly mixed. Those coins with higher grade silver are likely to be much better looking, while those with more copper have likely corroded. It looks like your coins on the left have a lot more copper in them than the one on the right, thus it looks "better". Since most of these hammered coins are dug coins, the silver won't be affected by the ground moisture as much as the base metal ones.

Sometimes these lower-grade silver coins have been plated with silver so that they look better and look like higher-grade silver and so those with full silvering will look better than a coin which had its plating worn or flecked off. Although I'm not sure if these coins were, there seems to be a lot for sale, but comparatively very little information on them.

For example, here's a British (Edward I) sterling penny:

View attachment 807000

Which is in fairly good preservation because of its high silver content.

View attachment 807003

This, on the other hand is a Henry VIII testoon (shilling) made out of debased (about 1/3 silver, 2/3 copper) and even though its nearly 400 years younger than the Edward I above, it is in worse condition because the elements attack copper more readily than they do silver, so the coin is partially porous and has a worse colour.

Henry V111 coinage was one of the poorest in English coinage, hence the reason he was dubbed old copper nose, because his nose would turn green because of the copper cores in his coins. The coins in the post are all probably billon, and unless they have a good silver coating, it would be best leaving them be.

SS

 

[hannahgodfrey]

These coins are antique and very valuable from historic viewpoint. I’d suggest not taking a chance by cleaning them and trying to make them look like new.

 

[sagittarius98]

I Think That
Lemon Juice seems to work best on the earlier better silver coins.Even those I am hesitant to soak longer than 5-10 minutes at a time.
The later types,esp. where there silver is less pure, I've had good success with coca cola.
Nice short soaks did well.

The value of the coin is ruined. I have never had luck with coca-cola, when I tried it on common coins. I put in a common German pfennig that was rusted, came out identical after 2 days.

 

[Silver Searcher]

I Think That
Lemon Juice seems to work best on the earlier better silver coins.Even those I am hesitant to soak longer than 5-10 minutes at a time.
The later types,esp. where there silver is less pure, I've had good success with coca cola.
Nice short soaks did well.

I have had ancient hammered coins in lemon juice for over week.....it does no harm what so ever.

SS

 

[orm25]

I found a way to make them look silver again. I did a experiment at school today with potassium persulfate. In a couple of seconds it was silver again.
I will post some pictures later

 

[orm25]

Here are the results of potassium perfulfate.