At the lab I work at when we were running film we never used PEC-12 to clean film for the reasons Athiril said. We did use it to clean prints without problems. For film we used cleaners designed specifically for film or anti-static cleaning cloths (great for removing dust). These usually wouldn't remove fingerprints, however. To do that the film was run back through some of the processing chemicals! I don't know exactly which ones because I didn't do it but it worked.