Cels Forum

Well, in my opinion I don't think you should put anything
behind a cel, since the cel will stick onto almost anything
behind it.  And yes they do stick to the cel bag over time,
but it's not really a problem since you can peel it off
easily without worrying much about destroying your cels.
Think non stick surface of a frying pan, sticks but easy to
get off.

What I do with each of my cels is I place them each even layers of multilayered cels into individual cel bags so
they won't stick to each other or their backgrounds (Talk
about obsessive).  This way I know I won't have to pry them off later and chip off the paint when I want to sell my
cels (When I grow tired of them) as to say "in perfect
condition, unstuck to background etc.."

So to recapitulate leaving your cels in their cel bags
won't hurt, I find them safer.  Anything else behind your
cels like tissue paper, wax paper (Oye!! damn wax paper),
etc... would probably be difficult to remove once the cel
is stuck onto them, that and it might rip off some of the
paint off your cels 
(me   wax paper   cel) = ((wax paper & paint) - (Cel   $$$))

Satoshi