The best way to get rid of it is to seperate the 
layers.  It's as simple as that.

Sometimes i find cels seperate better from the 
top, or different angles.  I had hopelessly stuck 
cels too where I had always try to seperate from 
one of the bottom corners.  But...Years 
later..Upon trying ot seperate it from the 
top...it seperated right quick.  It is totally 
weird O_o!  And this is still where it's wouldn't 
seperate from the bottom!

I'd do a look up on sepperating stuck layers, and 
you may wanna try to experiment tring to get the 
layer seperated...If you're feeling lucky...That 
is.  But...Try my idea first...and if it 
works...awesome...But don't ever force the layers 
^^;!

Good luck!