Best approach for dealing with bronze disease

[RL]

Ladies and gents, I have a couple of coins with mild bronze disease in my collection and having read the numiswiki entry on the topic and site hits a the top of a google search, I am curious about the best way to treat this. Everything I have read recommendes removing the green spots but from there it is not so clear and there seem to be differing views. When is it ok simply to soak the coin in distilled water? When is a Sodium Sesquicarbonate solution necessary and what is the risk in boiling the coin as part of this process? Some sites say it is fine others warn it can cause serious damage to the coin. Similarly the advice about drying the coin out by heating differs on the risk to the coin with some saying it can darken it considerably. Finally is there any risk in returning a treated coin to the container it was in while infected or should this be cleaned or disposed of? (I use quadrums for my ancients).

Thank you for your consideration

RL

[Joe Sermarini]

Do nothing until you have observed the coin and see progression of the bronze disease (active corrosion).

Most attempts to treat bronze disease damage the appearance of the coin. Most coins that are thought to have bronze disease by new collectors do not actually have bronze disease. Many coins that have what appears to be bronze disease do not need to be treated. Many attractive coins have been damaged by unnecessary treatment for bronze disease. Treatment for bronze disease is not trivial and should not be routine for the new collector.

Over several years, I gathered about 30 coins that had potential bronze disease and set them aside for treatment. They are nearly all different types and came from several sources. I set those coins aside well over five years ago and I never got around to treating them. I just looked at them again and not one of them has changed. Not one has progression of the "disease." They have been kept in a dry air conditioned house. I am not a new collector and I do have a good idea of what potential bronze disease actually looks like, yet I was once prepared to treat these coins when they did not need to be treated. Based on questions other questions seen on this discussion forum, some new collectors think ordinary patina is bronze disease. New collectors are likely to see bronze disease where it does not exist.

First, observe. If you do not see progression, if you do not see change, do nothing but properly store the coin in a dry environment and continue to check it.

True bronze disease is powdery and very light green. You can brush off or pick the powder easily. It is soft and does not adhere to the coin. When you brush off true bronze disease, it comes back within days or weeks. If it does come back then the coin needs treatment (and yes, a new storage container).

You posted your question on the "For the New Ancient Coin Collector" board. OBSERVE is the ONLY first advice appropriate for the "new ancient coin collector." If you want advice on how to treat bronze disease after you have observed your coins and actually see progression, then you should ask for help again on the "Coin Photography, Conservation and Storage" board.

I am locking this topic to ensure the only advice given here for the NEW COLLECTOR is...

Do nothing until you have observed the coin and see progression of the bronze disease.