I know some of the basic topics are covered in other threads (which I will search through) however I would like some general info from those of you in the know. First off most of the coins referenced were bought in the late 70's thru early 90's. I know many are in the old PVC flips. All have been in the bank lockbox. I noticed some are starting to show discoloration although many are still as beautiful as the day purchased. I have my reservations about an acetone dip for coins that do not need it. I plan on transferring all of the coins to safeflips. I noticed the larger coins (silver $1 and some halves) tend to show the toning (discoloration) on the rims and generally near the top, I wonder if this is the result of an old dipping by the dealer or possibly something caused by the staple which is only in the top. A couple of the V nickels appear to be the worst (which I assume may be PVC damage or verdigris?) Some of the other coins which range from xf-sliders I feel that the coloration is the result of a prior cleaning of one type or another. Ironically most all of the old BU copper indians and lincolns are still beautifully red or nicely toned down and radiant. This is one thing that leads me to believe that the majority of the issues are with a coin that was cleaned prior to my buying it and is now showing the signs of that cleaning or dipping. Even though I am hesitant to do so, some should probably have the acetone dip before being put in safe flips. Would you recommend doing only ones that show some sign of unnatural coloration, or all coins that have been in the old flips? I understand this stops the process but does not change the appearance or remove coloration, is this correct? If I simple transfer all coins to safe flips w/no acetone dip will the coloration worsen? (does this depend on whether it is PVC damage or verdigris?) Any suggestions would be appreciated. I don't want to make a bad situation worse by damaging coins that have no visible effects. Some may simply need a silver dip to remove some unsightly tarnishing. I plan on taking a representation of these with to the OHIO state show on Sun to show to some dealers. Would like to post some photos if I can figure that out. Thanks, Lackluster
Staples penetrate the protective mylar of 2x2 or flips due to its use. If the staples are not stainless steel, they can eventually corrode and whatever causes the corrosion can also affect the edge of the coin close by. They do make stainless steel staples, and would be much better. I have such coins from the same era Verdigris and PVC damage are 2 different animals. Acetone won't remove verdigris which is corroded metal. Verdigris has a metallic appearance , where as the PVC damage are caused by the organic additives to the PVC to make it flexible, and they result in chemical action that can corrode the metal. Acetone can remove such additives, but if the damage has started to the metal, the damage will remain, but be inactive if stored properly hereafter. PVC usually has a slimy green or blue green appearance. If Acetone takes it off, then it is PVC. The additive needs moisture and environmental gases to increase, so many coins in PVC holders may have an invisible adhesion and appear Ok. However, if improperly stored, can increase. After 10 or more years, the additives are probably outgassed, and the holders are fairly safe, but I would dip the coins in acetone and transfer to mylar lined 2x2 or the safelips you mentioned. Some will mention other storage such as Airtite (tm), but they are not air tight either. The best solution would be an inert gas, or a vacuum, but these are not usually feasible solutions. Verdigris or corrosion initiated by PVC , require environmental gases which usually contain sulfur, other corrosive reactants, and water to increase. Reducing these components help protect the coins. Some use Zip Lock bags for albums or bunches of 2x2s and this works well, although not the best for presentation PVC flips are still sold as they are inexpensive and flexible and won't scratch ( rub) the coin as mylar flip edges can. If I missed something let me know. Jim
