I'm a big fan of keeping multilayered cels 
unstuck whenever possible. Especially since stuck 
cels are prone to getting those infamous "oily" 
patches between the layers in unreachable places. 
I know there are at least a few people on this 
Forum who basically say "to hell with it" in 
regards to keeping cel layers unstuck, but the 
way I think of it is: If it's something I can't 
undo, I'm not going to let it happen in case I 
would have wanted it undone in the future.

But I don't know that wax paper is a good idea. 
It's not acid free, and it does eventually break 
down. I'll also bet it's possible for a cel to 
stick to it. (Especially a cel with that nasty 
black backlighting paint.) Not to mention that it 
can't be very attractive to look at. ^_^;;

What most people do is to put pieces of cel bag 
between unstuck cel layers. It's both acid free, 
and you can see through it -- the second of which 
lets you view your cels without needing to 
excessively handle them to remove sheets of wax 
paper. ^_^

What I wish is that someone could come up with a 
decent workable way to get a layer unstuck when 
you really need it to be. . .

Many Sharp Smiles,
--Drac