When to "clean" a coin?

I have an 1820 US large cent(will post a picture tonight), and on the obverse, there are two small spots of corrosion. If I remember correctly, one is over the "T" in liberty, and the other over one or two stars at roughly the 1 o'clock position.

There's turquoise discoloration, which to me, indicates corrosion of some sort. I'm also assuming that unless addressed, it will continue in some shape or form. In this type of case, what is an acceptable action to not further devalue the coin?

 

Log in or Sign up to hide this ad.

Is it green?

 

Greenish turquoise...I'll have to get a picture up tonight.

 

Sounds like bronze disease.

 

Not simple verdigris?

 

Looking at some images searching verdigris, that looks exactly like it. The searching also shows there are many solutions to getting rid of it. Does anyone have experience with this, that can recommend one method or another?

 

Photos, we need photos otherwise we are just guessing.

 

Without seeing it, off the top of my head.......Acetone bath first, then verdi-care.

Put post pics here first for other opinions.

 

Yeah, there was this product called Verdi-Care that was the go-to solution for verdigris. Unfortunately, it's out of production and unavailable at the moment, as best I can tell. Its creator is a member here (@BadThad).

 

picture attached here. what do you all think?

 

Yup, you're right. Verdigris, corrosion plus damage. Still not a bad looking coin.

 

That's verdigris. Acetone might stop the process. Try it once a week for about a month or so, then tuck it away in a 2x2 and see how it does over time. There's not much else that can be done. Some of it looks like it's etched in to stay, while the disturbance behind the ear and above the head might be of the type that can still be loosened some with a moistened toothpick after a soak.

 

How long should it sit each time I soak it?

 

That's verdigris so take measures to get rid of it.

 

Get some verdicare and soak in it will help remove and also stop it from progressing

 

Haven’t found verdicare available anywhere. Will the acetone work, and if yes, how long should each soak be?

 

The proper procedure is to soak them for 9 years, once a week, for one month...

OK, look. All it has to do is make contact with the acetone. The idea is to kill off whatever impurities are on the surface. When the acetone evaporates you’ll have a dry, basically inert surface. So really, just a minute or so will do the trick.

 

Acetone won't remove the verdigris, but it will dry the area and then as long as you keep it dry the corrosion will not continue to get worse. Basically you can't reverse the corrosion, but you can keep it from getting any worse.