A Complete Guide To Cleaning and Preservation of Coins, page 25
PRESERVATION, CONSERVATION and SAFEKEEPING OF COINS: Methods and Applications
A major decision for most beginners and even some experienced detectorists is how and where to store and display the coins found. If you are collecting coins, the following methods are to help you with that decision:
1) Mounting Coins on Trays, Displays: The most common way of preserving coins is to mount them on trays (boards, slides, drawers or the like) kept in cabinets or chests. Usually these trays are covered with cloth, velvet or velvet paper to protect the coins against loss in value from scraping or scratches while in safekeeping. These covering materials always retain traces of chemicals that ordinarily have no effect on the coins.
• If these covering materials, and particularly velvet paper, are glued to a base, then care must always be taken that the base has been thoroughly dried first. Otherwise there may be a generation of gas, such as hydrogen sulfide, which strongly discolors silver coins, especially on the side facing the material.
• Paper glue should be used as the adhesive since it is free of acid and alkali. Carpenter's glue or bookbinder's glue should not be used.
• A silver chloride coating, horn silver (described on page 2), occurs on coins if they are displayed on white, chlorine-bleached cloth.
• The wood in trays or cabinets can have similar effects on coins, which in this case tarnish or oxidize. The under parts of trays must be given a protective lacquer coating. Oak surely will attack silver coins, changing their surface into silver chloride (horn silver) because of the tannic acid in the wood. Mahogany has proven to be more suitable.
2) Plastic Bags: Another method of safekeeping for a coin collection, but even better for preserving duplicates, is storage of coins in cellophane bags or the stronger polyvinyl chloride bags which are as transparent as glass and allow the addition of an inscription or label. However, this material is dangerous for iron, zinc and aluminum coins which are ruined by it in a few years.
The corrosion may be caused by the following:
• Cellophane has a tangible water content. Over a period of time this, together with oxygen, produces an oxidizing decomposition of iron coins in the form of rust.
• Cellophane is very permeable to water vapor and highly hygroscopic (water-attracting). For this reason, bagged coins of base metals show even greater oxidizing tendency than those that are not enclosed.
• In the case of silver, it is attacked in a small extend by traces of sulfur compounds in the cellophane; silver sulfides are formed, producing the characteristic darkening.
• With polyvinyl chloride, metal soaps (tin, zinc and lead compounds) are incorporated for stabilization. If the action of these compounds is ceased, the natural aging of the film will release chlorine, which also can corrode the coins.
However, older silver coins can be kept directly in cellophane or polyvinyl chloride bags. Cellophane and polyvinyl chloride bags are very harmful for aluminum coins and tokens.
3) Coin Holders: The collectible coins can be packaged using the standard cardboard 2" x 2" coin holders featuring transparent plastic windows. The style that has self-adhesive sides is the most preferable, rather than those requiring staples. Coins mounted in holders can then be inserted into clear vinyl pages (with individual pockets) designed to accept a three-ring binder.
Many detectorists prefer to write the date, location where the coin was found and detector used on these holders. If a large number of coins is frequently found, handwriting this information on every coin can get to be extremely tedious.
Using a simple number stamp and maintaining an organized log of finds can be more fun and give a more professional look to your collection. It also gives you more time to spend on research and field search.
4) Coin Albums: The best coin finds sorted by type, condition and value can be placed in a specifically designed coin albums. The empty slots, which represent the harder to find type coins, are constant MOTIVATORS for any detectorist.
Another type of coin albums is the one that has removable binding pins in the spine and pages with rigid vinyl window inserts on both sides of the die cut openings. Albums of this type allow you to view the coin from both sides and insert additional pages for special finds as needed. Most coin albums fit easily in a home safe or safe-deposit bank box.
Different types of coin albums, displays, trays, and coin holders can be purchased on line or at any hobby shop or collector's store.
