Cleaning Pennies!

I'm impressed. Coins that are so dirty as to detract from their looks, I think, can be improved with a little bit of cleaning.

Can you tell me, is the mix pure viniger (no added water) and how much salt per vineger mix was used (the formula)?

Did you look at the last penny, the shiny one to start, under magnification to see if there were any changes? Do you know what the chemical reaction is on the surface of the coin?

Wouldn't it be wise to rinse the coin after the dip as some salt (or Vinegar) may remain on the surface of the coin and cause problems in the future?

Most collectors will say never clean a valuable coin as many people who do try and clean a coin will scratch the surface and do more harm than good. Nothing like steel wool to bring back the shine. The reality is that you own the coin and so you can do with it as you like. It's just a matter of when it comes time to sell the coin, someone else may not think what you did is an improvement. But then again there probably are a lot of people who will think it's an improvement.

Personally, an old worn out copper penny, that shows signs of heavy wear just looks wrong when it's completely shiny. I have an worn Indian Head cent that someone "cleaned" and I have had it for years hoping it will tone up again over time.

Thanks for the photos, they provide a very interesting result.

You are making a grave misunderstanding there Mooseknuckle. Here is an experiment to try out if you have the time to spare. Take two unc copper coins, preferrably off from the same roll to minimize enviromental difference. Leave one aside and let one in the solution like you described earlier. Put them aside and describe me the changes after two weeks.

There is one thing I would add - indeed you may think that the tarnished copper will be removed through the process, but remember, what you are doing is to strip a fine layer of copper from the surface and actually make it MORE prone to enviromental damage.

It is the same thing when you get a scar - do you try to remove the scar off but later realize that it will form a scab, or leave it alone?

I have done some experimenting with pennies also,using just a lemon or lime juice soak. No rubbing or actual cleaning. Under magnafication you could see that the juice had actually eaten away some of the coins surface, leaving a very slight, what could be described as a "matt finish". I don't know if your salt/vinegar soulution would do the same. You might want to check them under a scope.They sure look better to the eye though.

Vinegar = acetic acid. Acid + metal = dissolved metallic salt + hygrogen gas.

The chemistry behind your cleaning technique has nothing to do with sodium chloride salt, though perhaps it buffers the solution to some extent, making the reaction less vigorous and more controllable than straight vinegar or lemon juice.

Still, acidic cleaning does remove a thin layer of metal from the surface. The microscopic grooves and lines placed on the coin when it is struck, and which give coins their shininess, are particularly vulnerable - which is why acid-washed coins always look pale, dull or matte-finished. Acid can't bring the shininess back.

Another thing to be aware of - it's not just copper. Post-1982 cents are solid zinc, with a thin layer of copper over the top. Zinc is a much more reactive metal than copper, and if the acid breaks through the copper surface, it'll eat away at the core much faster. That seems to be what's started to happened on coins 6 and 7. The extra gas bubbling off of coin 7 is likely to be mainly carbon dioxide, from carbonate deposits on the coin.

As gxseries said, the coins should have a thorough wash after an acid soak, preferably in distilled water. Leave your towel-dried, freshly acid-washed coins out in the open air for a week or two and you'll likely start to see new pitting and corrosion appear.

As to why collectors object generally to harsh cleaning of coins, the main reason is that the damage is cumulative. Sure, one quick dip may not do too much damage, but after a year or two, you may dip it again.. and again.. then maybe the coin gets sold to someone else, who dips and dips... a couple more generations, and there's not much detail left.

Ketchup/Catsup is acidic. Don't think I would use it.

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Originally posted by sn31

I hav'nt been brave enough to try this,but I've been told to use ketchup on Indian Head cents?Anybody tried it?

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DO NOT USE KETCHUP TO CLEAN PENNIES!!!![:0] Oh my gosh, NEVER DO THAT!! [:0] Several months ago I was curious as to how using ketchup on copper pennies would come out. Using two useless pennies I put a drop on each and rubbed them between my fingertips. The results: The pennies turned into a dull pinkish, ugly color. It looked like play money. I would NEVER do this to any pennies I intend to keep.[:0]

Just for the record, Ketchup is the same as salt/vinegar ... Same with Tacobell Hotsauce. I tried using vinegar alone to clean a penny. No dice at all. Then I tried a bath of saltwater. Nothing ...

When you put the 2 together, it's magic!

I've seen that dull pinking color. In fact you can see it in one of the coins on my test website. It's strange though, because it only happens to a few pennies, and not all.

The penny don't look real I hate to say it but they look unnatural. Sure they are nicer than before sorta but they still look wierd to me. I don't know maybe cleaned aren't me