Hello friends,  I make jewelry out of ancient and irreplaceable old coins pre 400 AD.  What is the best and fastest way to clean bronze, copper, silver & gold.  any help would be most welcome.      Ripley

 sorry, the only way to remove patina that I know would probably not be appropriate on ancient coins - using fine steel wool to scrub it off. I am not experienced in this area. sorry.

Salt and vinegar pickle works on more modern coins but I'm sure I wouldn't want to use it on ones that were not easily replaced. One of the things that makes some of these very old coins so valuable is the patina which is what separates them from fakes. You just can't fake ancient patina that easy. The Chinese and the folk in the Balkans do a pretty good job a t faking ancient patina but you don't want to remove the real thing on bronze coins. Check with a numismatist for the best solution for this problem.

Thank you Robert,

      The one thing I found out last night is you can not use the silver cleaning solution of lemon/iron solution on bronze.  Sure it brings out the coper, but it corrodes the tin.  I used a worthless old coin to experiment.  Thank you all.   Traci/Ripley

I'm both a metal worker and a numismatist (coin collector) and have worked with coins dated from the period you mention.

 First-  DO NOT USE CHEMICALS/ABRASIVES, it will destroy the coin

 Coins from this period are in one of two states-  Buried loose, that is, they were simply in the ground.  With these the bronze has gone through a number of chemical/structural changes and has become brittle, you'll often find these in coin lots and auctions, uncleaned.   The other is wax sealed.  Soldiers of the period would often bury money in terracotta vessels sealed in wax to come back for if they survived the battle.  These coins are the most expensive as they are in far better condition, and behave more like metal coins.  These are the coins you'll find cleaned and pristine at dealers, for hefty prices.  These can be cleaned with coin cleaners you can get at a dealer.

 In both cases, esecially with the loose buried, you will encounter some pretty heavy encrustation, to a degree you may not even see the coin pattern.  Alas there is no quick way to rememedy this.

 Your best bet is to soak the coins in olive oil for several days.  Peiodically clean them with a mild soap and tooth brush.  You may need to ick at certain areas, which I would do with a toothpick rather than a metal instrument.  This will loosen the encrustation without scratching or damaging the already probably fragile metal.  Some you will be able to restore incredible detail, and when you're lucky, some may even turn out to be silver once you get the encrustation off.

Good luck!

Thank you my friend....I like your idea of using olive oil (kinda gives a historical Greek/Roman/Celtic) touch to my hobby.)  Ripley

You were sooooooo right about using olive oil.  I have had fantastic results.  Thanks a lot my friend.  Ripley  

Glad to hear they're coming out for you, I rather enjoy the process, it;s a bit like digging for treasure...

 Museums use a rather complicated device producing hydrogen in a heated atmosphere, this reduces oxydes whilst not corroding the metal. Unfortunately it's an expensive thing. The next choice would be to find an appropriate corroding agent to dissolve more the oxyde and less the metal. Ex - silver is not easily dissolved by hydrochloric acid because silver chloride is insoluble, whilst it still can remove (by turning it into flakes of silver chloride which can later be wiped off with a mild abrasive) both the black silver oxyde and related compounds like silver sulphide. For bronze, organic acids from the heavier serie (like propylic acid) work better as they don't dissolve tin whilst still getting rid of copper carbonate (the greenish stuff) and oxyde (the black stuff). After removing the patina it's wise to cover the coin with a thin protecting layer of varnish (e.g. acryllic) in order to reduce as much as possible further oxydation.