What To Do About Verdigris?

Thanks for the advice. How much olive oil do they need to be in? Do I need to use EVO, or will any olive oil do?

John Paul

There are lots of tips on what to do about those coins. Do a search on this forum, little thing at the top says search, for cleaning coins, verdigris, Olive Oils, Acetone, etc. There have been many discussions about things like that here. I presume what you show is only a small amount of them. What you should really try first is just soaking them all in distilled water prior to any and all attempts to get rid of that stuff. I mention this due to the possiblity of some of the coins may be rather on the valuable side. Not sure since you may have many, many more of those.
The main thing is to always try the cheapest, easiest, least dangerous methods on those coins.

I bought a bottle of BadThad's mysterious concoction and can say, after numerous experiments, that it is effective in fighting verdigris on several different metal types. It works BEST on copper coins with a fairly limited degree of verdigris corrosion on them. Some of the coins photographed in this thread would require prodigious quantities of BadThad's potion, and given their low value would hardly justify the expense, quantities of product, and time it would take to work their green down.

From what I've seen VerdigoneTM does not remove carbon spots (isn't designed to, for that matter). Also, I would have to say that VerdigoneTM is just about the most gentle, careful and coin-surface-sensitive way that anyone could take to interfering with the appearance (and/or conservation) of their coins.

I don't wish to raise the specter of that perennial debate, "to clean or not to clean," and the ethics of worrying about the condition of one's collection, but I recommend VerdigoneTM to anyone who wishes to battle the damaging corrosion of verdigris on their HIGHER VALUE circulated coins. It is not an end-all be-all, but one of a battery of techniques (including best storage and handling practices) that concerned coin collectors may bring to bear in preserving their holdings for posterity.

As an aside, let me say to John Paul that on coins that you know to be of little value, but whose appearance you would like to improve simply for your own enjoyment of them, and for which you know you will not be attempting to post slabbed consignments for auction with Heritage (!), honestly, I think you should simply buy a box of Q-Tips, a small bottle of the lowest grade cheapo olive oil (or a $2 bottle of Coin Care) and go for the soak-and-dab technique. Most of that unsightly stuff should come off pretty easily and no one will arrest you for irrevocably damaging the human cultural patrimony!

On Uncs, Proofs, and your very top dollar coins, don't mess around! Take 'em to a dealer if you want to know what if anything can be done.

I suggest being careful with foreign coins unless you really know what they are composed of. And too many other countries may not have documented exactly what is in those coins.
If in fact your mentioning Bronze coins, note the composition of Bronze can vary extensively. Brass is basically Copper, Tin and Zinc. Whereas Bronze is composed of many variations in materials. Bronze is usually also Copper and Tin but also contains such substances as Phosphorus, Manganese, Aluminum and even Silicon has been used to make Bronze. Bronze has many substances added to make certain aspects of an object appear differently. Some cleaning agents may well ruin such coins.
So if in fact your mentioning Bronze coins, you should be really carefull of what you use on them. On the Antique Road Show many timese they have warned people about messing around with cleaning Bronze unless you really know the composition.