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So I cleaned a small batch of copper pennies with a vinegar and salt solution. I let them dry on a towel after they were completely rinsed off with tap water. I was wondering
if they might change color or grow some kind of verdigris. I like my coins to be clean. I will not clean any numismatic ones.....
Has anyone else among our fine community done this before? Thoughts.

I am curious as to why you are cleaning them in the first place.

Vinegar and salt shouldn't make verdigris grow, but it also won't prevent it either.


Acetone works best! Acetone strips off the "luster", if the coin has any anyway, and should help prevent verdigris and stop it from growing.

As long as your coins stay dry you shouldn't be getting verdigris in the first place though.

This has been a running subject for some time, including a thread I started but, this one started by Shazbot57 some 3 years ago has some good info:

viewtopic.php?f=7&t=28565&p=255709&hilit=verdigris#p255709

Doc says he cleans his this way:

highroller4321 wrote:I am curious as to why you are cleaning them in the first place.

Vinegar and salt shouldn't make verdigris grow, but it also won't prevent it either.


Acetone works best! Acetone strips off the "luster", if the coin has any anyway, and should help prevent verdigris and stop it from growing.

As long as your coins stay dry you shouldn't be getting verdigris in the first place though.

I was only cleaning them just because I like the appearance of clean looking copper pennies, that's all. I was bored....
My coins do stay in a dry cool place, away from moisture or humidity.

hmm i was going to ask this same thing today. i got a batch that have been through a fire, turned very dark , purpleish and unreadable dates.

will be seeing if the acetone will do it.

So after cleaning the pennies over a month ago, I've noticed that they aren't quite as "shiny" as they were before. I'm guessing that it's just reaction between
the copper and the air. They have a dullish appearance now. I wonder if they will revert back to a darker brown color?

Oh well. At least they aren't dirty anymore!

I used to clean my pennies at work on my lunch hour. I work in a chemical plant and had every chemical you can think of at my disposal. I tried acetone, but not that great. I used acetic acid and that worked better. The best for was citric acid and boiling water in a plastic jar. Shake it around a bit let sit a couple of hours. Rinsed them off and scrubbed each one on a green scrub pad and they were like brand new. Ask Bob Baker about them. He bought a few CTU's from me. That process is over since I retired from Kodak in January and now I'm a full time stagehand.

SilverDragon72 wrote:So after cleaning the pennies over a month ago, I've noticed that they aren't quite as "shiny" as they were before. I'm guessing that it's just reaction between
the copper and the air. They have a dullish appearance now. I wonder if they will revert back to a darker brown color?

Oh well. At least they aren't dirty anymore!

It's called oxidation; yep, unless they are sealed with minimum oxygen, they will tarnish.

Way, way, way too much work for minimal (or no) return. I speak as one who has been collecting (and sometimes hoarding) copper cents for the past 55 years.