I have spent several years experimenting with various methods of cleaning ancient coins.
The following are my favorite methods.

DISTILLED WATER

This is a very simple and quite effective method for cleaning ancient coins that are lightly encrusted.
Secure a gallon of DW (distilled water) from most any grocery store including WalMart.
I suggest that you first scrub the coins with a dish detergent and a stiff toothbrush.
The bristles will not scratch the coins and there are many times when the brushing is enough to clean a coin.

Immerse the remaining uncleaned coins in the DW.
A one pint plastic container is very adequate.
I like to use a lidded container that allows me to gently shake or rock the coins every few hours.
Place your coins in the container until they are completely covered with the DW.
Allow the coins to soak for 24 hours, gently shake the container, and then pour off the dirty water.

Once again scrub the coins with the brush and detergent.
Remove the clean coins and dry with a soft cloth and put aside.
Rinse the container thoroughly after each soak.
Place the remaining dirty coins in the clean container and soak at least 12 to 24 hours.

Repeat as many times as needed to clean the coins.Eventually all the coins should be clean with the exception of the most stubborn which may require a different cleaning method.

OLIVE OIL

Begin the olive oil ancient coin cleaning process by scrubbing the coins with a stiff toothbrush and dish detergent.
Remove the clean coins and dry thoroughly with a soft cloth.
Place the remaining encrusted ancient coins in a one pint (approximate) plastic lidded container and cover with olive oil.

Soak the coins for several days.
The theory is that the thin oil will penetrate and soften the encrustation.
I believe there is an advantage to placing the container, oil and coins on a window sill where the sun can warm the oil.
I also believe the gentle heat speeds the cleaning process.

PLEASE DO NOT

Heat the oil on a stove or with a flame of any kind.
This would be very dangerous!
I will mention at this point that an invaluable aid to cleaning ancient encrusted coins are bamboo skewers which can be purchased by the dozens for a dollar or so at WalMart.
Please cut the skewers in half length wise and you will have even more cleaning sticks!

Remove the soaked coins after several days and scrub thoroughly with the toothbrush and detergent.
Repeat the soaking process as needed.
Use the sharpened bamboo skewers to prod and dig the dirt from the coin.
The bamboo will not harm the coin.
Metal will.
Some consider this to be a rather tedious process but conversely there are those who will use only the olive oil process.

TSP CLEANING

TSP is tri sodium phosphate and can be purchased at most any hardware store, including Lowe's.
Please READ ALL LABEL PRECAUTIONS before using and then mix as I suggest.
Mix one teaspoonful of TSP to approximately one cup of warm water.
Once again scrub the coins with brush and detergent.

Remove the cleaned coins and dry well.
I have found that one pint lidded plastic containers are ideal for this method as well as many other methods.
Of course, margerine tubs and other throw away containers work well and are free.
I save all kind of containers to use in cleaning ancient coins.
Place the ancient encrusted coins in the container and gently pour the tsp solution over the coins.

Avoid contact with eyes!
Cover all coins with solution and allow coins to soak for 30 minutes.
Some will say soak for 45 minutes but I prefer to err on the side of caution!
Remove the coins after 30 minutes and once again scrub thoroughly.
Remove the clean coins and dry.

Repeat this process as many times as needed to clean the coins.
Some coins will be very difficult to clean and may require many cycles.
Don't forget to use the invaluable bamboo skewer sticks to help prod and nudge the encrustation from the ancient coin!
As mentioned, some coins are terribly encrusted and are quite difficult to clean.
This brings me to my favorite method and the method I employ in cleaning most of my coins.

ELECTROLYSIS

As I mentioned, this is my favorite method for cleaning ancient bronze and copper coins.
I have worked very hard and spent hundreds of hours developing this technique.
I have used reverse electrolysis (I call this 'zapping' to clean thousands of coins and have developed what I consider to be the consummate method of cleaning ancient encrusted coins.

I also believe this to be the 'kindest' method of coin cleaning as opposed to those who scrape their coins clean with hard metal materials.
I believe in this technique to the extent that I have devoted a website on Yahoo Groups to this method.
I have so much material available on the site that it would be very tedious for me to repeat the volume of material here.
I have hundreds of other members who have joined and are now advocates of this method.

Please do yourself a favour and visit my site!

Please join and look at the information we have.

Feel free to ask all the questions you wish and I can assure you that you will be greeted by the friendliest and most caring ancient coin enthusiats on the web!

This is by far the most expedient method for cleaning coins and every week I have new members joining and for the first time after trying other methods of cleaning they are actually turned on to and excited about their new ancient coin treasures!

The URL is as follows:

www.ancientcoinstore.com

http://groups.yahoo.com/group.coinzappers

Thank you very much and God Bless.. Jerry..