I have had no problems what so ever with nail 
polish remover.  Computer plastic is also way 
different than cel acetate.  It's not like 
dunking a whole bottle onto a cel.  Just whatever 
it takes to wet a little Q-Tip.  I also said it 
was a riskier method and could remove paint (not 
melt plastic), and to try on a cheap cel first.

I've experimented with a bunch of solvents, and 
nail polish remover (at least the kind from Rite 
Aid) worked the 2nd best.  I have not seen first-
hand any warping or melting of the cel acetate.  
The only results I have seen are cels that are no 
longer cloudy.

I also probably have a steadier hand than most 
people, heh.  Yeah, if someone is a clutz, then I 
wouldn't recommend nail polish remover or 
cleaning in general.  And in that case, it'd 
probably be best just to find a lighter backdrop 
to put the cel against to mask the cloudiness.

Oh, I've tried the alcohol cleaners as well.  I 
would recommend ethanol over isopropanol (and if 
you worked in a lab, you'd know why).  Alcohol 
does remove spots as well, although it didn't 
work as well as the nail polish remover for me 
anyways.  Now I just use whatever leftover 
ethanol I have left to clean my scanner bed.

Later, yo.