Removing Masking Fluid from Negatives

[Vincent Brady]

Any suggestions how I might go about removing masking fluid from some of my 35 mm B&W negatives without damaging them.

 

[payral]

Most of the time is part of masking fluid instructions

 

[AgX]

To my understanding there were two sorts:
the rubber one, to be peeled off after setting and the red varnish type to be wiped off with solvent.