I have an old Lincoln cent collection. Many have been stored away for 25 or 30 years in an old Whitman album, the kind that has two clear plastic slides that go over and behind the coin, and the coin is inserted between them in a cardboard-like hole. Several of the coins have isolated spots of green corrosion on them. Often they are very tiny spots, and some have an almost hairlike look to them when under a 10X loop. A few spots are larger and are plain to the eye. Even in the "worst" case, the area affected is a small fraction of the surface area of the coin. Will this green gunk grow, even if the coins are now removed from the old album and put into a new Littleton album? Can I clean the coin with something that will arrest it? I know that you're never supposed to clean a coin. I just don't want this stuff to grow all over the coin. At the same time, if it's taken 30 years to get these little spots, then maybe I'll be long dead before it's a worry anyway.