Hello Collectors, I am worried about my slabs after hearing about Intercept Shields. Apparently it is a good idea to put them in the little slab boxes to keep them from over time getting toned and corroded. How does this happen if the slabs are sonically sealed (I have PCGS and NGC) and do I have anything to worry about? I like toning, and I do sometimes spend premiums on toned coins, but their are some coins that I would prefer to be white and I'm just worried that the slabs aren't enough protection. Thanks
Slabs help, but aren't good enough on their own , even sonic sealed, they are not water or air tight. Corrosion/toning can be caused by Moisture ( water ) , air ( containing sulfur or other corrosive chemicals), contact with electrolysis causing substances, and unusually energetic light such as bright sun, or UV. Most is caused by the first 2, the other 2 very seldom if not intentional. Intercept technology utilizes activated copper based material that will react with sulfur and other corrosive substances easier than the coin will, and thus "reduce" strongly the possibility of corrosion/toning of the coin. It doesn't eliminate moisture, nor is it "forever". In serious atmosphere contamination, the active copper will become ineffective, in normal conditions~ decades. A dessicant chemical can absorb moisture, but it also is limited and may have to be recharged. Some have recommended using archival epoxy around the edge of the slab, but I feel this is not a good idea since it may be ugly and certainly almost impossible to remove. If one doesn't mind the appearance, one of the best is to put the slab into a food quality zip lock bag ( with or without dessicant ), squeeze the air out, and zipping it shut. If one is really paranoid about the zipper leaking, fold it over and tape it to the bag. Change bag if it becomes worn. IMO. Jim
