MS70 copper over time

Zoins

If a copper coin has been treated with MS70 and attains a "MS70 look," will the surface of the coin continue to change over time?

Goldbully

Definite Rick Snow question.

Walkerguy21D

Not sure how long of time period you are thinking, or what the storage conditions are for your question, but I have a few Indian cents, Canadian cents, and misc darkside copper coins that were treated ~5 years ago and stored in 2x2 cardboard holders, that have not changed appearance at all.
Maybe if they were stored in a Dansco album or left exposed to air, they may change more readily.

Zoins

Thanks Walkerguy21D and Goldbully.

It's good to know this type of surface is stable. I'm looking at a coin which may have been treated this way and was wondering if it can be expected to maintain it's look or if it would degrade.

Walkerguy21D

On the flip side, if you want to get rid of the effects of MS-70, Blue Ribbon will readily eliminate that light bluish frost.
Use it very lightly (if you can find some), otherwise you'll replace the frost with an oily look.
I don't know if acetone will also remove that frost or not - if so, then that may be a better option.
Then of course the purists will tell you to just find one that has not been treated with anything.
But in my case they were low value coins from a large estate that weren't stored properly and had hazed over, and
I personally think these are much more attractive now, even though they are not 'original'.
And I can now spot treated coins in dealers' cases quite readily!

EagleEye

Definite Rick Snow question.

Once a coin is cleaned, it may open it up to the effects of the atmosphere, whereas an uncleaned coin has a stable surface.

Zoins

Good to know Walkerguy21D and Rick. Still thinking about whether to pull the trigger on this one.