Help with Old Coppers!

[TreasureHead]

Someone know what's going on with these buffalo nickels? I regrettably and unknowingly cleaned the first couple coins with salt and vinagear, and now this is happening.. Every time I wash this green calcium like substance off with hot water, it returns! Is there anyway to salvage these coins?? Any info is much appreciated. Have a great weekend!

 

[Southern Brass]

I myself have encountered the same problems you are having with the green gunk returning on the coins after cleaning them. I have found that after cleaning with salt / vinegar solution try lightly rubbing them with baking soda then rinsing with water. I guess the baking soda neutralizes the acid in the vinegar. Also when the coins dry I lightly rub silver jewelry cleaner on them to prevent tarnishing. So far this has worked for me. It may not be the right thing to do but hope this helps you