Had a new casette installed and after a week or two it's already as if there is a black matt tape inbetween the 4 most used sprockets. I mean a matt black that's all around the center axle. I can clean the sprockets themself/the sides. but not at the bottom.
Just bought a tool to get it out but it doesn't even come close to removal-should I use sanding paper or what? (not that I will do that - most likely is that I will leave it - ). Any tips?