Expert: PAPAJACK - 6/22/2008

Question
Every thing I have read says only experts should clean coins. That being said,we have suffered a flood here in Cedar Rapids IA. A lot of my fathers coin some in books folders sleeves and a lot just loose are contaminated with some of the nastiest gunk that You will ever see. We are told that you can't even touch stuff with out gloves. I got a little cut and it was so infected after 8 hours that my hand began to swell and required antibiotics. My father is 77 and cant be in contact with this stuff until it has been disinfected. There is no way we can clean each and every coin with alcohol. we need to at least clean the gunk off first. We have most every thing bagged right now. I started to rinse some coins with the hose then dip it in bleach then rinsed it real well.As the silver dries it begins to turn dark . Am I doing more harm than good? It has to be cleaned some way. Is there a better way? Is there a professional service to use? Some of this stuff is common silver some has been graded and a lot of it has been mixed together,silver and copper, old and new. Please help

Answer

Hello again George,                       
A friend and conservator added;

You are correct in being worried about the toxicity issue with the residue on the coins.

It is important that the collector somehow record the curatorial information that is contained within the books/folders/albums.
Upon removal from the holders the information will be lost. Even if they take a digital image of the housing before it is disposed of I think that will help in the long run.

Originial answer below;..

Hello George,                                 

Let me first state as a Coin Collector that coins are worth much less to coin collectors after having been cleaned. There is usually no reason to clean a coin. Unless the substance is destroying the coin (like acid, PVC damage etc.). Any coin that has ever been cleaned will sell for less. Collectors don't recommend cleaning coins at all.

When a coin is cleaned the original surface is removed thus removing the luster that the purest collectors want to see.
The cleaned surface allows other contaminates to attack the surface. Also the cleaning may deposit other particles on the surface.

Cleaning of Bronze, Copper, Silver or any coin can render it virtually valueless! Collectors would rather have a dark deep chocolate brown specimen or spotty brown than a cleaned coin. Even rubbing a high grade coin with a very soft cloth can leave minute scratches on the surface that will adversely affect collector value. So be careful.

Now for your immediate question;
Your coins do have to be cleaned somehow. Alcohols may be best at this point to stunt the organic contaminating them.
You found you are correct in being worried about the toxicity issue with the residue on the coins.  

It is important that all the collectors somehow record the curatorial information that is contained within the books/folders/albums. Even if they take a digital image of the housing before it is disposed of I think that will help in the long run.

You did not give me any specifics on the collection; you should probably target more expensive coins first. You can find them by looking in a copy of the RED BOOK titled " A GUIDE TO UNITED STATES COINS " by R.S. Yeoman or other catalogs that are "Guides" to coin values and grading, the current value for most US coins is considered to be a standard it will let you find the coins that are more valuable and rare coins just by looking down a column. Although the prices are not accurate a rare coin stands out in the price guide as many dollars more that the one before and after it.

I would find out if there are any high value coins or sets in the collection. You may want anything really rare like an 1889-CC dollar or 1909-s VDB cent restored or curated by a professional.

Do not use bleach! Only PH neutral solvents and distilled water are used. I have also seen Lacquer Thinner, Acetone, and alcohol used to remove dirt. If you have modern proof coins since 1968 they may be ruined with spots and such but must be removed from the holder.

Use gloved hands, Playtex or surgical rubber will do. It is easy to leave fingerprints on silver coins. I prefer cotton gloves if the coins are not contaminated. Wear protective gloves and get the coins out of any card board holders or folders. You may want to make a list of any information on the coins as you take them out of the holders.
Give them an initial rinse in clean water and pat dry.

I would separate the coins into Tupperware bins also put desiccants like silica-gel in the Tupperware and storage area.

Be careful the coins dent easily hitting each other.  If the coins retain their original surface they will be more desirable as I said. Original coins often have a CARTWHEEL or starburst effect (mint Luster) when tilted in the light, this even shows through the natural toning colors.

I hope this information helps. If you want I can help put you in touch with an American Numismatic Association Member near you.  Just write me back, give me the nearest large Cities, some postal zip codes and telephone area codes. I will refer you to an expert in your area for a free opinion.

Good Luck

PapaJack