It all depends on "where" they are kept, IMHO. Toning can happen with naturally occurring gases known as "environmental" coin damage. It can happen with humidity, "bleeding" of harmful plastics, wood, paint, and chemicals just "
nearby" your coins, temperature, etc., etc.....lots of things.....and only time will tell with some coin compositions, as far as "how they're doing" with
where they are currently kept.
2x2's certainly aren't "airtight"......nor are home safes.
The majority of my collection is in Safety Deposit Boxes at my bank, which has them located in the "center" of the bank, climate controlled. But even that, guarantees
nothing, as far a "toning prevention" ! ....
