There is a lot of bad information about coin cleaning. Scan the "net" and also read the comments on some of the coin forums, and you will seen lots of bad information. You need to always remember that information on the "net" is not always good, sound advice.
You need to be very careful with your cleaning if you use a metal detector to find coins, especially any copper, or metal other than silver. Most times badly damaged copper coins that have been in the ground for many years will not clean.
I will try and give you the best information and the techniques that prove to be the best when cleaning coins. The information here is about the techniques used to clean coins from change or found in the ground using a metal detector.
You should never attempt to clean a proof coin or any coins purchased from a coin dealer where the coins are contained in folders. Most often coin cleaning these coins can cause scratches, or oxidation.
If you are a treasure hunter, and you use a metal detector to locate coins, then the information here will help you in coin cleaning those old as well as new, clad coins.
However, before I begin, it is important to understand that if you do use a metal detector to locate especially old coins, then cleaning may actually take away from the old looking effect of the coin.
For instance, if you like the look of the green patina found on many of the oldcopper coins like Indian Head Pennies, as I do, then cleaning them may remove the patina. You need to ask yourself before any cleaning takes place what kind of effect you want your coins to achieve.
The Soapy Bath
You need a plastic container, do not use any other container, you could scratch your coins if you do.Fill the container with warm water. Add a small amount of detergent; mild dish washing detergent is best. Gently add your coin, or coins into the container, rub both sides between your fingers, and be very gentle here. You don’t want to scratch the coins. If you add more than one coin to thecontainer, be careful you don’t have them scratching each other while in the mix.
Rinse, Rinse, And Rinse Again
After the cleaning, put the coin, or coins into another plastic container of distilled water. This is a rinse that is used to remove any grit that may be on the coin. Again, be very careful.
When your finished with the distilled rinse, you need to rinse the coin again, this time under running water. Make sure you get all of the soap residue off and any extra dirt or grit that may still be on the coin. Remember to be very gentle; it doesn’t take a lot to scratch your coin.
Your last rinse in coin cleaning is to be in your container of distilled water once again. You want this rinse to remove any excess soap, and grit, as well as chlorine that is on the coin.
Time To Dry
After your coin cleaning you can leave your coin on a dry towel to dry. The distilled water used in the rinse process will not leave any minerals on the coin. So your coin should dry without spots.
The Electrolysis Method
Before you attempt the electrolysis method understand that you can get severely burned by coin cleaning with this method. Be extremely careful.
Your going to need to gather up some items before you begin to clean your coins.
You’ll need an AC/DC adapter. It can be a 9, 12 or 18-volt type. The high voltage does work better. You can use an adapter from an old phone for this method.
You also need two alligator clips. Radio Shack has them. You can also purchase the clips at a hardware store. Stay away from the copper clips.
Also needed are a stainless steal spoon, a glass, and some salt.Now strip the end of the wires on the adapter. You need to separate them first. Attach an alligator clip to each end.
Add some water to the glass and about a half a teaspoon of salt.
Now you need to attach the negative clip to the coin and the positive to the spoon.
Which Is Positive
To find out which lead is positive you need to follow this very carefully.
Drop the spoon in the glass and attach one of the clips to it. The other clip goes to the coin.
Plug the adapter into the wall outlet and then drop the coin into the glass. Be sure the coin does not touch the spoon. If the spoon bubbles, switch the clips around.
If everything is right, the coin will bubble.
In a few minutes your coin should begin to loose the crust that has built up on it over the years. You’ll notice the gunk in the glass. Your coin should be clean in about 5 minutes.
Coin cleaning with this technique is used best with older coins. You may need to experiment with different amounts of salt for best results.