The plastic liner (teflon?) is actually the "lube" -
Did you check to see what was binding on the cable to make it ball up?
... something grabbed/chaffed on that cable to peel that stuff off, so if left unresolved, the next thing will be to eat through the cable itself & no amount of grease nor silly-cone spray lubricant will "fix" that!.
It could be that the clutch tube broke loose & it's moving around as you use the clutch caused the chaffing. Look at both the firewall & in the tunnel by the shifter to see if it's loose. It's a common problem in 914s, & there was a topic here in the Garage on fixing it within the last couple of weeks. BTW - it you can move the tube around at the firewall, then both F&R welds have broken loose, if not then you still need to check the front one in front of the shifter.
Also make sure you have a good ground strap & connections from the transaxle to the chassis (up under the rear trunk), as long as you're trouble shooting this problem.