The jar has been sitting undisturbed for over a month and a half now. During that time it was frozen solid for about 2 days (the barn is un-heated). The original set up and explanation can be found here.
The photos clearly show the amount of “fluffy” material formed. I have to guess its something like aluminium hydroxide. You can also see in the photo where the strip was wiped off, that there is a bit of erosion on one spot which corresponded to a location with the white deposit. Its funny how localised these areas are, open to conjecture.
The stainless steel sample was unchanged.
My next step is to make a series of metal pairs and immerse them in a range of liquids. I’ll do that after Christmas.