Peerless Milk, Etna PA, Rainbow inside bottle

[kranked003]

I've got a Rare milk from Peerless out of Etna, PA. It has developed this odd rainbow coloring on the inside of the bottle. It is not within the glass, it's on the inside. Its kind of flaking off and only visible under certain lighting conditions. We never noticed it before and I don't believe you can see this when it's sunny out.

I'm looking for any explanation for this phenomenon.

Also, I've had a collector say he really wanted this bottle, but I'm not sure what it's worth. To me, "really wanting" it means I can up the price, right?

 

[kranked003]

I've got a Rare milk from Peerless out of Etna, PA. It has developed this odd rainbow coloring on the inside of the bottle. It is not within the glass, it's on the inside. Its kind of flaking off and only visible under certain lighting conditions. We never noticed it before and I don't believe you can see this when it's sunny out.

I'm looking for any explanation for this phenomenon.

Also, I've had a collector say he really wanted this bottle, but I'm not sure what it's worth. To me, "really wanting" it means I can up the price, right?

Where's my milk guys?

 

[macjxl]

I've got an amber quart that displays a similar phenomenon on the outside of the glass. I always figured it was a mineral reaction due to being buried in wet soil for some decades. I'm not a fan of tumbling so it is what it is - patina. As far as pricing is concerned, If the collector is very keen on your bottle, they will probably make a fair & reasonable offer for it. When you say "up the price", up from what? If you are too greedy, you may lose your only potential buyer. That's not to say that haggling is out of order. Watch The Life of Brian.