I've been following this topic on usenet (alt.toys.transformers) in the last couple of weeks, and thought it very informative for all fans to know how best to preserve their toys for as long as possible.
The topic was about the main elements that deteriorate plastic in toys, and the surprising one (to me) was the third one - contact of different plastics (like the toy in a plastic bubble, both carded or boxed, because there are *dozens* of different types of plastics). UV light from the sun had been common knowledge, and Fluro lights is a little bit more disputable, but the contact of plastics has me thinking that in the long term, a figure out of packaging is going to be better off than one in packaging. So not only figures that have batteries a ticking timebomb, but now collectors with MISB/MOSC (Mint in Sealed Box/Card) figures could now be sitting on toys that are slowly eating themselves away. But in the short term, their value won't be affected, especially by anyone wanting to buy them to keep sealed for display purposes. This topic just counters any claim by sealed collectors that their figures are better off in the long term. Not something to suddenly panic about, but older figures and transparent ones are already being found to be affected in their sealed packaging.

The issue with clear Transformers has been raised too, in that figures are showing yellowing in their sealed packaging, but it is uncertain if that is due to plastic-plastic contact, or some small exposure to UV or fluro lighting to start off the process (it might not take much to affect clear plastic).

One thing that concerns me is that Fluro lighting could be deteriorating or yellowing my toys, and in a few years time, the tradition lightbulb will be illegal in this country (the law was passed last year to help counter the greenhouse effect), so it could mean I should get UV resistant perspex doors attached to my display cases to protect them from my fluro lighting.

The google groups topic link:
http://groups.google.com.au/group/al...6a9cc913bbf119

Some of the highlights of the topic:

Going thru some research material recently (after having a conversation with a starwars collector regarding his storage methods for figures...breathing was involved), I came across a few notes I took regarding issues you can have with how you keep your tfs:
1) flourescent light damages them. (seen them yellow when displayed under one for a few years...even when the light is six feet away)
2) sunlight damages them. (we've all seen this happen to that jetfire left outside)
3) contact with other plactics...ie, their bubbles, damages them.
(elvin pena's clear prime is a fine example of the yellowing from this
process)
However, noting #3 above, it occurs to me that even a ziplock bag touching
my tfs is probably not a good idea. To say noting of their inability to
breathe in a rubbermaid tote/ziplock bag. Should I switch to
archival-quality plastic, such as the type used on my old comics (and old
tfs)? Should I go back to the wooden drawer or plastic drawer system?
I'm uncertain of the reason toys would need to "breathe" while in long-
term storage. I'm not a physicist, but wouldn't the exchange of
particles in the air contribute to entropy; i.e., oxidation of the
screws and metal pins, chemical breakdown of the plastics, etc.?
I've been annoyed at how my Action Master weapons have discolored.
The easiest example is Grimlocks tank/cannon. The orange trigger
faded years ago. Oddly enough, this isn't true of the rest of the
orange plastic. Just the trigger. Other Action Masters weapons that
use this orange plastic have similar issues: certain whole plastic
pieces are faded, but others aren't, even if they appear to be the
same color to start with.
I keep my Takara Clear Screamer in it's box w/its plastic trays (all in a cupboard) , and admittedly have noticed some mild yellowing of
the clear plastic . :-/
It never occurred to me that it was because of the contact with it's
plastic trays -- but now you've made me wonder if I should remove the
toy from it's packaging .

While working on a project a few years back I discovered that all of my
beast era stuff that was encased in ziplocks had yellowed substantially,
ruining hundreds of units. Also, I had a G1 Red Alert that was downgraded to Yellow Alert with a touch of Brown Alert (and I'm not really sure what
that means... but I bet it's not pretty.)
I also was looking at the missiles for my OmegaPrime/God
Magnus/whateverthehell they call it clear sparkly giftset recently, which I
had foolishly left in the plastic tray. They are discolored on any part
which was touching the packaging. Those parts are basically irreplacable, but I wonder how all the sealed ones have fared... badly I suspect.
You need pvc-free plastic materials to store a toy for any long period.
Since the plastic used on the bubbles and inner packaging the toys came in is *NOT* pvc free, eventually those units left sealed will deteriorate,
which is yet another good reason to collect loose units. I'm sure you've
all seen the pictures of nice minty units that are horribly yellowed on the
bubble. This is the fate of all sealed toys. It's only a matter of time.
Climate and storage precautions will help stave off the eventuality... but
never stop it.
Wait, waitwaitwait. Come to think of it, I actually *have* seen an
example of this happening. I finally decided to bust open my carded
Star Wars Episode I version of R2-D2 because I needed it for a
project, and I was surprised to discover that the little flip-open
panels on his body had turned yellow. I figured they'd just used a
bad batch of glue to assemble him or something, but in light of this
recent discussion I wonder if it had to do with being in the packaging
for so long. (And that toy has only been in storage for eight or nine
years.)
It gets better, Zob. The toys themselves are also not PVC free. Google
MEGO toys for some great examples of toys literaly eating themselves up due to the chemicals used to create them.
Vintage GiJoes (60's, not 80's) also get "pinhead" syndrome, where the head shrinks due to being different plastic than the body.
Granted, that's 40 years... but G1 Transformers are halfway there.
In the case of your R2, it was likely the softer plastic used on those
panels that felt the effects first. Did the toy itself or the packaging
cause it? Who knows... but it puts the MISB collector into a more rarified
and even more tenuous market.
My *beautiful* MISB Pepsi Prime's box was all wrinkled up when it took it
out to inspect it a few years back thanks to some unknown humidity issues at my apartment. It just about killed me. I still didn't open it, but I know that the Styro will also eventually eat the toy... so it has to come out sometime.
Regarding #3, Yes, contact with other plastics can cause plastic to yellow, but more often than not, this yellowing starts with the bubble
or packaging. If you notice the packaging starting to yellow, take the
toy out of the package! The value of the toy will drop further in the
package than out of the package at that point.
The toys themselves don't need to "breathe", but the Ziploc bags need to
breathe, else they will start to turn yellow and damage the toys inside.
I guess the moral of the story is that our toys were really never
meant to last forever, so we should not expect them to. Perhaps, we
could seal them in glass cases filled with inert gases, but what would
be the fun of that? I suppose that is what we get for considering our
toys as long-term investments (either for pleasure or money) rather
than taking a more accurate, transient view of them ... here today,
gone tomorrow.
I agree with the last sentiment - to me, they are and will always be, just toys, not an investment. I'll play with them as much as possible while I still can, because none will last forever, and if I ever grow out of collecting them, at least I had as much fun as possible from them.