I recently acquired an Esterbrook J transitional pen. It is in need of sac replacement. I have worked the section loose so it rotates around within the barrel but I cannot remove it. I've tried heating, pulling, tugging and twisting to no avail. When looking down the barrel I can see the sac appears to be a gooey mess. Could this be the reason I cannot remove the section? Any suggestions would be appreciated.

Regards,
NK