What is this?

Here is one from a few years ago.
Look Like it just came out of the mint | Coin Talk


If you look closely at Lincoln in the photo you can see the partial copper that didn't get fully removed.

 

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I know this is not exactly the same as the original pic but while at work in between customers I played with a torch lighter and this is the result. This is just a torch and a quick douse in water. You can see evidence of heat on this one but also the zinc is exposed. I wonder if in time the evidence of heat would disappear.

 

I don't think that's exposed zinc. I think it's chemically altered copper. You could test that by putting into water with some lye (drain cleaner) dissolved in it. If the central area starts bubbling, it's exposed zinc; if not, it's copper.

(Careful with the lye water! Don't get it on your hands, ESPECIALLY don't get it in your eyes, and flush it down the drain when you're done.)

 

Learning things everyday. I don't have any lye but gonna try it out. I have been skeptical about missing clad layer zincolns ever since I did this years ago.

 

That definitely isn't exposed zinc. It is discolored or toned in the center.
How do I know? It has the same tones and characteristics of soldering plumbing joints.

 

Couldn't one just use a commercial dip? Yes the copper would turn pink, but it would clean the oxidization off the center plating.

 

Whoa, whoa, whoa, that's what I was forgetting -- when you heat the copper plating enough, the zinc underneath dissolves into it, forming an alloy with a different color! Bake a Zincoln, and the whole coin will turn to that "gold" color, because you've turned the copper plating into brass.

 

And since I was wrong about the oxidation -- I'm not sure what the dip would do. Time for more experiments!

 

I am trying to imagine your garage/ home office. Bunson burners, beakers, test tubes.

 

All the chemistry stuff is packed away. It's not nearly as inviting now that I'm paying for homeowners' insurance myself.

 

again I just was pointing out that it looked like zinc exposed. just saying