There not proofs. And they were already doomed. I'll tell you one thing though. These are the worst mint sets I own, dipped or not.
I think you did misunderstand. I went back and read the other thread, and the only person saying anything about contamination was you. One other poster complained about mint sets of that era tarnishing, and not being good for long term storage, but nothing about contamination. I have sets from that time period and they are just fine, but I am careful about where my coins are stored. I think the problem comes in when the packaging isn't completely airtight and they are stored in an environment that causes the toning. A careful dip with a product made for coins may be alright to help with the toning if you don't like it, but this is definitely overkill!
I would leave them alone. If worried about the mint packaging, a quick acetone rinse and put them in different holders.
@bruthajoe You can continue to experiment from now until the proverbial cows come home, but quite literally everything under the sun has experimented with ten thousand times over. And even when used properly, there is a very short list of things that will work and not permanently damage the coins - a very short list ! And pretty much all of them can cause damage to a coin when used improperly.
rubbed them, i see small circular marks when blowing up the photo?? see i am wrong, but i think they looked better before..
That has nothing to do with luster, and besides, while that nickel is a little "spongy," those dies aren't in any late stage so as to reference as deteriorated.
