Vinegar and salt !

Ok then before you all tell me off !! ? for cleaning, I have only done a few coins that are not valuable and are not in my main collection.
I tried a couple of silver halfcrowns and some farthings, great results but how do I remove the pinkish colour on the farthings ?
Silver is fine,

Cheers

Bob

The "pinkish colour" comes from the damage done to the surface by the acid ... you made many little craters in the copper surface which break the light differently so the only way to "remove it", is to polish the surface smooth again ... so you have nothing gained
I can only advice against any attempts at cleaning  alloys with high copper content.

I went through the same phase. If any acid or abrasive is used to clean a copper coin, it is basically ruined. It will takes years to regain some patina. Silver coins fair better, but the coin will still be damaged to some degree. A good way to clean copper coins is to use hot water and a mild soap, like Dawn dish washing liquid, to clean the coins. Afterward soak the coins in rubbing alcohol for a few minutes and then let them air dry. I would recommend the same thing for silver coins. If they are uncirculated silver, you might dip them.        

I have used Olive Oil and Acetone to clean up Copper/Bronze coins with good results.

baking soda is effective and due to how fine it is, the coins do not get scratched. It wont remove any patina, but it will remove dirt and grime that hasn't been on the coin for very long.

I works well on coins in poorly sealed mint sets if you want to remove the "Toning", even though it is a build up of dirt and gets called toning.  If it wont rub off then it is the real type of toning due to age.

I'll try that out, fluke. Thanks

I have used it on 1970's British mint sets that have become grimy toned.

Like this 1970 proof that was a mess.




I added a few heaps of baking soda to a little bit of water to make a paste, like runny yoghurt consistency.

dip the coin in and then gently massage the coin between fingers and thumb, dont worry about how hard you apply pressure, it will not scratch the coin. after a few "dips and rubs" it will look like this.



You can see there is still some minute staining left on the coin, that would have been the very beginning of the toning which is now set in the metal.

But it sure is effective without needing anything chemical or abrasive.

Cheers guys and I don't even feel told off lol.
That's a great result fluke on the penny, think I'll give that a go , cheers

I think all of us have got that itch to clean a coin.   

Silver coins are my nemesis, I like nice shiny mint looking silver and it takes everything I have got to not clean my pre 1900 coins  

If you want to clean a silver coin, use same method I said but after dipping in the soda paste, get a small square of Aluminium foil (Yes America, it has 2 i's, always has, always will   ) fold it in half, put coin inside and rub the same way, between thumb and index finger, i do NOT mean slide the foil around on the coin, flatten the foil on each side over the coin and slide your finger/thumb over the top of the foil. You will start to feel it get slightly warm, that is a reaction between the soda, silver element and Aluminium. it can be very potent depending on silver content of the coin (potent as it will clean faster the higher the silver content) normally this method will clean a silver coin in any state to a bright mint state shine, but still no scratches.  

this will be nothing less than mint shine, if you want to just remove grime and retain the aged look/patina then do not use foil and the soda will clean all the greasy fingerprints and dirt that has accumulated over time.

Like this 100Mils I found in my very first huge joblot, it looked like it had lived in a public toilet for years, completely dark brown and unrecognisable. Cleaning without the foil gave this result, shame I didn't take a pic before, but you can see the point I mean, it will clean off anything that isn't infused in the coins surface.



just to clarify something which can confuse some.

Baking soda & Bicarbonate of soda are the same thing.

Copper coins are very delicate. But sometimes there so dirty that you want to try something.
So I tried the baking soda too:



A lot of dirt was already gone and I even didn't do it the right way. I took some water and then I put the baking soda in it but the baking soda didn't solve in the water so I hadn't a paste at all. So next time I take some baking powder and I add a little bit of water instead of taking too much water and add the baking soda.
Anyway, the result was already wonderful. Click on the pictures twice to enlarge and then you see how big the difference is (f.i. the crown) between uncleaned and cleaned.

Thank you very much Fluke for this hint.

Glad to Help  

This was the result after cleaning it when I made a paste of the baking soda, with left the original state:



An example of a copper-nickel coin:

Citação: muygrandeosoI have used Olive Oil and Acetone to clean up Copper/Bronze coins with good results.

Same here, I preserved  nice 1740 1/2 Penny using this method.

If you get a coin.... Can you tell that it is cleaned with baking soda paste the way you guys describe or is it impossible to say it has been cleaned. What about looking at it with huge magnification? Can you tell then?
Thanks in advance for answer.

The only product I have ever come across that is practically untraceable is Verdi-Care. Once you treat a coin with it, the appearance it better than you can ever imagine, even.with severely corroded coins.

With baking soda and vinegar, one most likely would be able to know it has been cleaned.

You will be able to tell that around high elements like letters that there is an older surface and that is a significant indicator of cleaning ... also soda paste, as fine as it is, is an abbrasive (like toothpaste) and rubbing it all over a coin will leave its marks, they may be small but they will be there.
But on the shown examples that had allready significant wear I woudn't care they look much better and have less possible corrosion starting points.

Damn.... Ok... If it's identifiable I think i will pass...

But yea, with some cheap coin that otherwise is unidentifiable or in so bad condition that it would otherwise be a useless coin for me anyway, i may try.

it is all down to the coins initial state, the soda paste will only remove a thin layer of dirt that has accumulated over the last couple of years, rule of thumb is you never clean a coin anyway, but coins you want for your own collection can be your own choice for them to be more pleasing to the eye.

Bicarbonate of soda is said to be non abrasive no matter how hard you rub with it, but without being an expert I cant comment for sure, my other method of cleaning will definitely be picked up under a scope, that one is for unrecognisable coins.

TSP (Tri-sodium Phosphate) will also clean grime off of copper without removing the patina. The only caution is that if you make up a batch and use it over and over, it pretty quickly deteriorates and will turn your silver brown. For dirty copper I just mix up a batch with hot water and let it soak for a bit, then rinse with clear water.

I use electrolisis to clean my coins, however you need to have one of these. It will remove rust oxodisation and dirty very quickly and does no dammage to the coin, simply use water a small amount of sodium and some tin foil, connect the coin to the nutral and the live to the tin foil, then put the foil in the water, suspend the coin in the solution and turn the current on, you want less than 2v and .5 amps, this can be achived using wire and a AA battery but will not be at effective as using my transformer/volt meter. Will try to make some videos and upload on youtube for all to watch.