The *only* way to keep layers separated is with 
archival polymer sheeting (i.e. cut up bags made 
from polyethylene, polypropylene, or mylar). I'd 
recommend 1mil thickness at most, and  
polypropylene instead of polyethylene of Mylar  
because polyeth warps too easily at that 
thickness and Mylar is too 'sticky'. 

Some people bag the separated layer setup in its 
own baggie and then bag the WHOLE thing including 
the background, but I think that would get a 
little too thick if you have many layers.. You 
might want to try different things, like sheeting 
only the painted portions; I've even heard of 
people cutting shapes out of their sheeting for 
a perfect 'fit' because lots of polymer layers 
makes the colors duller. 

I just use a Qtip and rubbing alcohol to clean up 
my cels, but I plan on buying the photo gloves 
eventually... 
^_^