i've read some of the toning threads and still have a few questions: 1. how does one detect AT vs NT? it seems nobody is 100% not even TPG, so is there a sure way? 2. if all coins exposed to air will tone to some degree over time, isn't the coin you are buying/collecting today going to change unpredictably? How many people are keeping their toned coins in airtite holders in controlled environments as opposed to slabs? And won't this certainly change the TPG grading so a slabbed toned coin may no longer match the grade. It seems you can at best slow down the process but you are basically buying/owning a coin during a portion of it's lifetime not knowing what's going to happen to it. Or is past toning an indicator of future toning so once it starts toning you know the path it's going to take.
Short answer - no. Even the best of the best of experts cannot definitively say that a given coin is AT or NT. The current determination is to say if the toning is market accpetable or not. Yes. Toning cannot be stopped, but it can be slowed way down. First of all there is no such thing as an airtight coin holder - none. So no one is keeping their coins in them. But there are several holders that greatly reduce air circulation around the coin and thus slow down toning. Slabs are only one of these options. As to how many people use them and then store their coins properly - not enough. Only a small percentage of collectors use the right kind of holders to begin with. Fewer still then store them properly. Not necessarily but it could. Coins can and do tone inside the slab. And if the toning is allowed to progress to the point that it becomes corrosion then the coin would no longer even be worthy of being in the slab - it would become body bag material in other words - let alone maintain the assigned grade. Conversely it is also possible that additional toning could improve the eye appeal of a coin thus increase the grade. You know nothing, toning is 100% dependant upon storage methods and environment. Vary them in any way and everything changes.
