You can't just stop with that vague description! 
Exactly which restoration company, and what do 
you mean about "mixed results?" 

I'm sure that more than a few of us here would 
be very interested in knowing in just how good a 
job a restoration company (e.g. SRLabs) would do 
with separating a stuck sketch from the cel. 
There are certainly a bunch of cels I'd like to 
separate from their sketches if I knew that it  
could be done.