I am frequently asked what is the best way to clean my metal detector coin finds? I am as adamant today as I was 40 years ago. If the coin has potential numismatic value, do not clean it. I repeat-DO NOT CLEAN IT! Cleaning a valuable coin will greatly lessen its value permanently. However, many metal detector coin finds can be cleaned to enhance putting them back into circulation. I have given several methods for cleaning coins in previous articles and here a few more simple methods that anyone can use.
Clad Coins are the easiest coins to clean. If you make a mistake and they look bad, who cares? They are still spendable. I use my tumbler for cleaning clads. I have a double unit and fill the first tumbler about half full with quarters and dimes and nickels and add water about a inch above the coins. Several commercial cleaning agents can be used but my favorite cleaner is ivory soap. I slice a small bar up and put several slices in with the coins and let the tumbler do its job. I half fill the other unit with clad cents and clean in the same manner. This will take the dirt off of them but not stains. To clean stains, I soak the coins in a cup of white vinegar and a tablespoon of table salt. It is best to soak them overnight. Afterwards, I put them back into the tumbler one more time. The pennies come out good enough to return them to circulation. Never put copper cents into the tumbler with clads, as the nickels, dimes, and quarters will come out a copper color.
Common date wheat pennies also can be cleaned in a tumbler. Some will come out looking pretty good but badly encrusted coins will not be enhanced my tumbling. I take joy in putting the old cleaned wheats into the hands of young children in my ministry. I also use them in my Easter Sunday metal detector plastic egg hunts. The children have a blast finding the eggs with coins in them and many have never seen a wheat cent before and I get to share coin history with them. I have had some good success using Dell Darkener on some valuable copper coins finds to restore them to a natural tone after cleaning.
Cleaning common date silver coin finds is easy for the most part. I use a soft toothbrush with warm water and soap. This is usually enough to enhance the appearance of the coin. Many silver coins come out of the ground encrusted or stained and electrolysis or the vinegar soaking method might be needed. These methods might leave them with a dull silver color and an application of Wrights Silver Cream will return them back to a bright color. I would not use this cream for valuable silver coins as the value will decline. I sell a lot of silver metal detector finds as coin jewelry pendant sets and this cream is great for making good to fine condition coins look great as jewelry pieces.
For the most part, I will not clean older non-silver metal detector finds. Buffalo Nickels, V Nickels, Shield Nickels, Indian, Flying Eagle and Large Cents should not be cleaned by any of these methods as value will be destroyed. Never use bleach, gasoline, ammonia or other household cleaners on coins. Likewise, no acids, and I mean no acids should be used on coins. Remember, NEVER CLEAN VALUABLE COINS!