Trying to clean pennies found near salt water turned white

[Bev]

Hi,

I found a few modern pennies on a very rocky beach area on the salt water edge. It almost looked like they had barnacles. I soaked them in peroxide but they turned a chalky hard white.

These werent anything interesting but what did I do wrong so I don't do it again?

Thank you-
Bev

[Iron Patch]

Must have been a chemical reaction with the salt. Peroxide doesn't tend to help salt water copper finds, and the problem is not much else does either. We used to hunt the shoreline quite a bit here but gave it up due the condition.

[Bev]

Oh, well that's bad. Alright, maybe I'll fool with a few different experiments with a few not so valuable modern pennies!

[Bev]

I emailed the department head of the University of Saskatchewan because I had found a thesis written by one of his students about, "EXPERIMENTAL STUDY OF REVERSE CREVICE CORROSION" in 2005. Which was a study on corrosion on long term exposure in salt water of copper piping.

I explained why I was looking at it and what my problem was (among many ) and he forwarded it to one of his experts to review it. Maybe he'll get back to me with something interesting! Wouldnt that be neat?

[xasp61]

did you try a tumbler? a drop of dish soap and some aquarium gravel and just enough water to cover the gravel. Might take a couple runs to flush out the salt. let me know if it works.

[Bev]

I think my son and I would love to play around with a tumbler. That is also on my Christmas list!