Someone once posted that s/he gets their cels 
unstuck by placing it facedown and rubbing their 
fingernail over the edges of the stuck areas 
(kinda like you're scratching the paper around 
the edges of the stuck patches). It's supposed to 
loosen the paper fibers. I tried it on cels that 
were stuck in many little patches, and it did 
help a lot in removing the sketch, with little or 
no damage to the sketch.

Yes, my cel has become one with the sketch. If I 
didn't love both the cel and sketch so much, I 
would just peel the sketch off. I don't wish to 
send it to a restorer because it's bound to cost 
more than the $20 I paid for it.

~Queenie