Bronze Disease, Beyond Help?

Also, is it dangerous leaving coins in distilled water for too long? what would be the limit, as I am currently trying 'extra patience' with water before moving on to olive oil?

Yes, any that you care concerned about keep separate. Once you have got a coin to a standard that you are happy with, consider getting some renaissance wax to preserve them.

http://www.ebay.co.uk/itm/RENAISSAN...em1e873ac4e6

Make sure they are thoroughly dry first, bake in a hot oven.

Once you have used the wax you will be unable to do further cleaning, so do not use it as an interim measure. The British Museum uses it and you can find a lot of information on the internet.

It is not as expensive as it looks, a small tub of the stuff will last you for years.

Not on coins though.

Hi MIB,

From the photo, your bronzes look disease free. I purchased a batch of bronzes a while back, and was disappointed to find that they looked like this-



I could tell something had been eating away at the coins from the pitting, and they were covered in a very light green powder. My first experience with bronze disease. They weren't exceptionally valuable coins, so I decided to do some research and see if I could salvage them. I tried soaking the least infected coins in distilled water for months. This eventually got rid of enough cloride ions to halt the sustaining reaction that is bronze disease on most of them.

2 CuCl + H2O = 2 HCl + Cu2O
(stage one)
2 HCl + 2 Cu = 2 CuCl + H2
(stage two)

The more heavily infected coins I soaked in a solution of sodium sesquicarbonate(soda ash and baking soda)for weeks and then switched them to a distilled water soak. This treatment can be a double edged sword. Using a solution over 5%, I was able to halt the bronze disease on all the heavily infected coins in the lot, but it also stipped the patina off of them. In my case saving the remainder of the coin was worth losing the remaining patina.

Firstly, doesn't look like BD and should come free in cleaning. Secondly, yes, there can be issues with leaving coins in DW for too long, mainly tranfering BD from one to the other very slowly over time.

I give all my uncleaned coins a couple of weeks in DW, changing regularly, just incase theres even a bit of BD unseen on there. Then, sometimes ill go to olive oil, but I've started staying with DW because its cleaner and easier. I still put tough coins into long term oil baths.

Also - dont go from olive oil to DW, because you'll have oil residue on the coin and the water wont be able to permeate. And it also goes moudly and nasty in the DW.

I was curious. As a coin collector, are you better off trying to salvage a BD coin even if it means losing the patina? Can metal cleaners like Flitz and Sea Power Metal Polish stop the BD? Or are you better off sticking to the safer methods (distilled water or oil) in hopes you save coin and patina?

Thanks Victor. If I decide to treat any badly diseased coins again I'll experiment with a baking soda solution.

Once you have seen many coins that have had an attempt at being cleaned in an electric bath, there is no mistaking them.
Personally, I would do what you can with a brass brush with these and then leave them with a coat of clear cherry shoe polish for a few days to help get rid of the 'dry' texture they have.
The cherry shoe polish is pretty much a match for the over rated renwax, but it is missing the perfume - it is a lot cheaper though.
The coins you have have defo been stuck in an electrolyses machine, over cooking always gives the same effect. Get some cherry on them and leave them a few days.