Cleaning Coins With Salt?

[DeoxyriboNucleicAcid]

Alright, I was doing an experiment with stelactites. To make this short... I took an old, black penny to weigh down a paper towel in a nearly saturated solution of salt, and water. The penny was wrapped in the paper towel, and then submerged in the salt solutiuon (NaCl and H2O).

A day later, when I took the old penny out, it was as good as new!

Can someone explain this?

Will the penny get more rust after soaking in the solution in the long run, or is it a good cleaning??? Is this cleaning method practical for coins, and does it cause any damage???

Thank You.

[BPHgravity]

Some collectors like coins to be clean and free from tarnish. Others feel they should not be touched and the "patina" left alone. Removing tarnish from silver does take a slight amount of the silver with it, so I imagine the same goes for copper and copper alloys.

[Tesseract]

Well I dont think NaCl is able to clean the pennies.

Salt mixed with vinegar or lemon juice cleans the pennies becasue the two chemicals make hydrochloric acid.If you want to know heres the equation:

 

HC2H3O2 + NaCl --> HCl + NaCH3O2

 

 

CuO + HCl --> CuCl2 + H2O

[DeoxyriboNucleicAcid]

hmmm, could you extract the HCl from the vinegar/ NaCl mix?

By the way, I am soon going to try the experiment with a penny wrapped in the towel in water, and the penny alone in SALT water. This will tell me which one of the two (saltwater, or towel) is cleaning the pennies. Although it may be a combo, as the paper towels i buy are soaked in chemicals anyway before i even get my hands on them...

[Tesseract]

hmmm' date=' could you extract the HCl from the vinegar/ NaCl mix?

By the way, I am soon going to try the experiment with a penny wrapped in the towel in water, and the penny alone in SALT water. This will tell me which one of the two (saltwater, or towel) is cleaning the pennies. Although it may be a combo, as the paper towels i buy are soaked in chemicals anyway before i even get my hands on them...[/quote']

 

Well if pennies just had dirt on them you could clean them of by water.But the pennies are dirty with copper oxide.You need a strong acid to take it off.

[YT2095]

Well I dont think NaCl is able to clean the pennies.

Salt mixed with vinegar or lemon juice cleans the pennies becasue the two chemicals make hydrochloric acid.If you want to know heres the equation:

 

HC2H3O2 + NaCl --> HCl + NaCH3O2

 

 

CuO + HCl --> CuCl2 + H2O

WHERE the hell did you get that from? it`s complete garbage!

the ionisation potential of organic acids is no where near strong enough to displace the sodium ion to free the Chlorine to bond with a Hydrogen!

 

are you saying salt and vinigar on Chips makes Hydrochloric acid? ROFLOL

[Tesseract]

WHERE the hell did you get that from? it`s complete garbage!

the ionisation potential of organic acids is no where near strong enough to displace the sodium ion to free the Chlorine to bond with a Hydrogen!

 

are you saying salt and vinigar on Chips makes Hydrochloric acid? ROFLOL

 

One moment please I saw it on....

[YT2095]

it`ll make copper acetate or copper citrate, that`s all!

[Tesseract]

Heres the whole thing from someone called Jessica Blindt.

Equation:

 

HC2H3O2 + NaCl ---> HCl + NaCH3O2

(vinegar) + (salt) ---> (hydrochloric acid) + (sodium acetate)

 

CuO + HCl ---> CuCl2 + H2O

copper(II) oxide + hydrochloric acid ---> copper(II) chloride

 

the site is...http://www.elmhurst.edu/~chm/demos/ShinyPennies.html

[YT2095]

well she`s wrong

[Tesseract]

Whats the equation?

[YT2095]

Cu + 2 H3C-COOH ----> Cu(H3C-COO)2 +H2(gas)

vinegar copper acetate

 

taken from: http://www.madsci.org/posts/archives/dec97/877613842.Ch.r.html

 

basicly it acts as a carrier, s&v will not make hydrocloric acid outside of equilibrium ballancing

[Pleiades]

I was going to make a new topic, but I searched first and found this highly relevant thread, so I’m dusting it off.

 

Why is a mixture of salt and vinegar often recommended as a cleaner? How is it any better than plain vinegar? (I’m trying to clean some really tarnished brass)

[gcol]

Salt is/was a traditional mild abrasive used in all sorts of mixtures to clean metal. The secret with salt is plenty of hard rubbing. Might just as well use pumice powder or toothpaste. No "secret" chemical action, as I remember it.

[John Cuthber]

OK, YT2095, perhaps you would like to explain how come it works better with the salt since you think the only reaction is with the acetic acid?

[cameherein2020]

What up! I know I am about 16 years late but, I just wanted to point out that (like others have) @Tesseract was incorrect in saying that salt and vinegar makes hydrochloric acid. I dislike the spread of misinformation. Next time make sure something is correct before you post it to the internet. 

 

Also I made this account to post this. But I'm sure nobody will ever see this. I put so much time and effort into doing something so utterly pointless. 

Edited February 18, 2020 by cameherein2020
Wanted to say more

[Huckleberry of Yore]

In my youth I cleaned coins dug using a metal detector with baking soda and water.  Worked for old pennies, and brightened silver nicely, although as noted previously, valuable coins should not be cleaned like this.

[MigL]

Your efforts are appreciated, Cameherein2020.
Stick around, there's plenty of misinformation on the internet, that needs correcting.

[Strange]

10 hours ago, cameherein2020 said:

I put so much time and effort into doing something so utterly pointless. 

I think you have just captured the entire philosophy of the forum.