So there is no definitive answer for plastic box 
framing? After reading the above I took down all 
three cels. I want to display these, but if it 
will damage them I will take no chance.
These frames were had at michaels for about 5 USD 
a piece. They are fairly thick. I had no clue a 
simple room light would have that kind of effect 
over time to the cels.

Luckily they have not been up long. 
I wish there was a cheaper way to safely frame 
cels, the ones I have are by no means priceless, 
but I am a Hhuge Fatal Fury fan in general, so 
each one is priceless in my eyes.
Reading a few threads I also see this is probably 
the one downside to cels.

Pictured below is the Tony cel acquired from 
Anime-Taro.com, I am very pleased with this cel 
and much like the Krauser ones, I want to keep it 
safe.