I remember a couple methods in sketch removal I 
have read about, and I feel it is my time to try 
some.  I heard you could put the cel and sketch 
into a freezer to try and remove it, but about 
how long should one leave it in there?  If I 
leave it too long, will it damage the cel?

I also tried the scratching method but that was 
insufficient.

Is there any other methods I can use to try and 
separate the sketch?  It is stuck, but it is not 
stuck to much of the cel, so I know it can be 
removed.

Any help will be much appreciated.

Thanks!