Cleaning coins with vinegar and salt??

Well, couldn't that be construed as a....(wait for it)....natural cleaning process?

 

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IMPROPER.

 

Not quite, I'll call on @BadThad and any other chemists to back me up on this. I ran into this as a method to clean copper cents even as a wee lad. Doing the "Silver Penny/Gold Penny" experiment with high school kids, this came up again. I always wondered how or why it worked, but was never curious enough to spend much time digging out info. Vinegar is a 5% solution of acetic acid, a weak acid that is only partly ionized. I would assume the role of the salt is to increase the acid strength of the solution so as to allow the acid to function. That being said, ifn you start with clean coins (pretreatment) and remove all trace of salt (posttreatment), there shouldn't be THEORETICALLY nothing much wrong with the procedure. The devil would be the removal of all the salt, which would lead to enhanced decomposition.

 

Should see what happens when North Korean and American coins come in contact:

 

I'll certainly defer to @BadThad, but I'm pretty confident that acetic acid is more than ionized enough, and salt's completely ionized, so you're going to have chloride ions and protons (actually hydronium ions) -- so it's at least the moral equivalent of hydrochloric acid. Dilute, as you say, but dilute HCl is still destructive, because that chloride ion loves to make off with metal ions. (That's what makes it more destructive than other acids, even when it's dilute; it's also why aqua regia attacks gold and platinum. The nitric acid oxidizes, the chloride complexes and carries away.)

 

As a strictly chemical reaction it's one thing, but I was left the impression (not having watched any of the videos) that there was mechanical action involved as well. Wouldn't careful and thorough rinsing with water remove the salt sufficiently?

 

Like showering after you get out of the Great Salt Lake? Yeah, I guess so.

 

Lots wrong with this.

 

I think that is the problem. Copper is a particularly tough beastie to do anything with.

 

You take a longer shower.

 

how looooooooooooooooooooooooooooooooooong?

 

Until the ocean's surface is measurably lower.

 

Waiting to find out what, with bated breath -- partly because I'm really interested, and partly because I don't like breathing nitrogen oxides.

 

Nitrous? Oh man, you need to get out more.

 

Wondering about the mechanical versus chemical action myself...

 

I think vinegar and salt is a ladies hygiene product.

 

Only Walking Liberties

 

People who go slower than the speed limit in the left lane are also a ladies hygiene product.

 

You got it! Chloride is very destructive to metal.

 

I think you can make a battery with this stuff.