Question about MOC figures discoloring/deteriorating
 

Hey all-

So, I have FINALLY gotten around to cataloging my toy collection after 30 years of collecting. Unfortunately, as I am opening boxes and cataloging, my stomach is sick from the amount of mint-on-card action figures that are actually discoloring IN THE PLASTIC.

I have spent the last hour scouring the web for answers and really, I haven't come up with much that matches what I am noticing. Most discuss the effects of the elements/heat/light on loose figures, but I have yet to read anything from collectors noticing this from fairly curated, MOC action figures.

So, let me clarify the details so anyone nice enough to answer doesn't jump to conclusions:

-I'm not a professional using acid-free protection casings, and no, not all of them were stored in plastic Serilite-type boxes (although over half are.); half are in typical cardboard.

-My figures have primarily been stored in 3 places in the last 30 years.
a) A storage unit inside, but underground.
b) A downstairs closet in a spare bedroom.
c) An mainfloor closet in a spare bedroom.
a & c were both in the Seattle area, so yes, damper climate.

-The figures that are affected are all sealed & MOC, and the discoloration appears to be on particular pieces of the figure: full arm or leg, etc.

-The discoloration appears to be like a haze or fuzz...it almost looks mottled. The color is always lighter and faded.

-None of these figures have ever been exposed to sunlight nor extreme heat or cold. ALTHOUGH, my wife recently reminded me that in the main room closet, a few boxes may have been closer to hot water heater (albeit, heavily insulated.)

Now, I have read on one particular post that this can be typical of cheaper plastics used by some companies; that they can deteriorate quicker. Yet, I cannot seem to find much information following up on that. For what it's worth, I have noticed it (in my collection) ONLY in older DC Direct figures, DC Universe mini CRISIS figures, DC JLU figures & DC Universe figures. At least so far (and I am 75% through my collectiom.)

Anyway, I appreciate any input and/or help on this. Quite perplexing indeed and enough to make a collector sick to their stomachs. :/

Thanks all...