Hi Sandra,

Yeah, I don't see any way to reverse this kind 
of damage.  I remember way back someone once 
suggested the possibility of warming the paint 
enough to be able to mix the background paint 
with the cel paint so it becomes unnoticeable.  
While that is a clever idea, I would have no 
idea how to do it without damaging the cel 
further. O.o

Anyway, background bleed through is not as 
uncommon as you might think.  I've seen a couple 
dozen or so cels with this problem over the 
years.  Sailor Moon cels seem to be particularly 
susceptible, most likely because of the quality 
of the paints used.  I’ve even seen a couple of 
cels that had the lines of a stuck pencil sketch 
leech through to the front of the cel. *sigh*

I do not understand why some stuck cels end up 
having this problem and most others do not.  
Like you, I worried that all my stuck cels may 
eventually have this problem and for a short 
time I tried removing my stuck cels from their 
background.  But that is a delicate task and can 
take a lot of time so I rarely do it anymore.  
Over the years I have been collecting, I haven’t 
seen cels develop a new problem or worsen once 
in my possession.

I would probably remove the background from your 
cel as nesuferit suggested to prevent further 
damage.  To do this, I would *very* gently and 
slowly pry the cel from the background.  It can 
take some work to pry off the parts that are 
solidly stuck, but it can be done.  The biggest 
danger is having the paint chip off the cel, but 
if you do it carefully enough it shouldn’t be a 
problem.

IMO, I would avoid fully wetting the 
background.  The paints they use on them 
(especially on a purple/blue background like 
yours) are very intense and I would be afraid of 
staining the clear acetate if you got the 
background wet.  Also, the background would be 
salvageable if you pried off the cel rather than 
wet it.  Once the cel is removed, you will 
probably have some paint and background residue 
left on your cel that you can remove by soaking 
in water or with a soft wet rag.  Even by doing 
this, I found you can’t remove the entire paint 
residue from the back but the majority will come 
off.

~Luna-Art >^.^<