Fokkusu said:
I also have some cels that were stapled to the background. If that's the case with these cels, do not ever try to separate the layers. The staples could shred the cel.
Actually, you really need to separate the layers. The staples can and do rust, and that can damage your cel.
I use my fingernails to unhinge the staple, and then slowly separate the staple from the layers. It takes a while though.
On another note, I would not suggest separating the acetate layers if the paint has stuck together, though. If you really need to do so, like in cases where there is moisture inbetween the layers, take it to S/R Labs instead. It takes them a while and the process isn't cheap, but if it's something special to you that you want to preserve, they're the best option around.