I have my upstairs wall covered in figs in protecto packs. One thing I noticed this week while dusting the cases off is that the ones right outside the bathroom door had a huge buildup of what appeared to be dust, it actually ened up being the wife's hairspray reside(basically a white dust)
I used a wet paper towel to wipe the cases, but I noticed a few no matter how much you wiped, a few of the cases had kind of a "rough" feel to them on top, so it appears that the hairspray may actually break down(or blend into) the plastic ever so slightly.
So, gotta remember to try to keep any figs/bubbles away from hairspray.
Just an FYI.