What Would You Do If You Had A Bunch Of These...?

what are they? (sorry I cannot tell from the pictures). Any writing on the 2X2?
Also, how many do you have? do they all look like this one?

The damage may not be from PVC (which usually creates greenish residues on the surface of the coins), but simply from excessive humidity or other inadequate storage conditions. Where were they stored and for how long?

Pictures of other coins from your collection would certainly help.

Part of the frustration is not not being able to identify them. This is just the first example I picked out - some of them are labeled and some not (this one unlabeled). I would guess from others I've opened that is a British Penny, possibly Australian. Many have a white residue like this one that mostly stays on the plastic when I open it and some have the green residue you mentioned that stays mostly on the coin when opened.
These have all been stored in sheds/garages/attics in North Texas since probably the late 90s. They are all from my wife's late grandfather who collected and sold coins for probably the last 40 or 50 years of his life.
I read about PVC residue remaining on the coin and continuing to damage it even after reholdering and I want to avoids that. It seems that acetone may be the best option.
I should add that these are mostly foreign coins with some Lincoln Memorial cents mixed in.

I'll try the rinsing and acetone bath on that coin tomorrow and upload pics and try to give you a better idea of how many coins are in this condition. Thank you for your replies!

That appears to be mold, not PVC damage. The 2x2 white flips did not usually have PVC for a film material owing to its relative thickness.

The general appearance of the staples, the paper, and the inside of the holder are, to me, consistent with mold and humidity damage from storage inside a high-heat, high-humidity environment, possibly in the presence of fertilizers, whose dust is highly hygroscopic (attracts moisture.) I have also seen this with flood damage.

I think it is mold. Take it out (while holding your nose) Rinse it with water. Don't rub it. Just let the water run on it. Then bathe it in acetone

Shows evidence of humidity damage from fluctuating temperatures in the storage area. Humidity rises and fales ans so does temperature. As the temperature falls the water condenses out of the air. (Notice the staples are rusting.) The 2X2's are not airtight and the water and any chemicals dissolved in the water gets deposited on the coins. The the plastic tends to hold the water and chemical inside with the coin. Perfect environment for chemical corrosion to occur. This is why attics, basements and garages are NOT good places to store coins. Coins should be kept in relatively cool low humidity areas preferably ones that are temperature controled or at least do not have wide swings in temperature.

Here's about 2/3 of the collection. Most of the paper baggies have wheat cents in them including cracked skulls, clipped planchets, unrolled edges, etc. The tube is Steel cents. The last pics are some of the worst with rust, green and white residue.

I am feeling optimistic. Let us know how the rest come out.