Gori prop internal fouling

[Pine Painter]

Wondered if anybody else has had problems removing the hub of a 3 blade Gori folding prop due to accretion of calcite inside the screw cap.
We are cruising in tropics and have removed prop for first time since new (after 20 months). It was very hard to get the front cap to unscrew, sea water gets into the cap and in high fouling waters (SE Asia) calcite deposits build up very fast. Has anybody else encountered this and how did you resolve the issue. I have ideas based on experience thus far and wanted to hear from anyone who might be a stage ahead of where we are with this issue.