I recently received a WWII commemorative half in an NGC holder graded MS69. It has what appears to be ugly gray toning on the reverse just on the top left. Is gray toning natural on clad coins? also would a coin with such ugly toning grade MS69 and if it was put in the holder before the toning occurred, would the toning happen so relatively fast? It theoretically could have been in the holder for about 19 years. Thanks for all input.
Most certainly and most holders do not prevent toning. I pull older uncirculated coins from their cello mint packaging all the time having the dull ugly gray toning on them. And yes, they can still have a grade of MS69 with such toning. I've seen some horrible ugly toned coins grade just as high. I dislike toned coins, not a big fan. If it happens then it happens but I definitely don't buy coins based on whether or not their toned or not.
Talk to anyone who has been through a flood. Coin holders from the TPGs are neither water tight or air tight. Your best defense is to keep all coins in your collection (slabbed or raw) in a controlled environment. It also brings up the saying so often repeated here on Cointalk: Buy the coin , not the slab. By the way, good catch on that coin! Some people don't bother checking the reverse of a graded coin all that close. Many assume that an MS69 is next to perfect in all ways.
