GC controller joystick mechanism.

[lawliet]

Few weeks ago my original GC controller main analog stick started to fail when moving up and down, now it does not move all the way up or down.I disassembled it and found that the joystick mechanism have a white stuff that is broken/worn out.I have found some replacements on ebay and I can replace the whole thing but i would like to know if there is a fix for it before i replace it.Any idea?