Many thanks for all the suggestions. I spoke with the plumber who did the original installation and he said he had used silicone sealant rather than plumber's putty. He also stated that 50% of the jobs done around here (southeastern NH) are done this way.
His suggestion was to apply force...
I'm trying to install a new kitchen garbage disposal and have arrived at the point where the existing flange in the sink must be removed. All the bolts are off but I can't get the flange to come out. I've tried banging on it from the bottom (first resort of the beginner!) and have tried getting...