How can I get black streaks out of rough leather shoes?
You can get rid of black streaks due to scuffing on stairs or the gas pedal, for instance, with a kind of rubber eraser, such as Salamander Velourlederreiniger, Coxy D�tach� Daim or Woly Gum Velour. These products also help clean greasy spots.
How can I get ballpoint streaks off of rough leather?
Put adhesive tape onto the ballpoint streaks. Use your fingernails or a hard object to scratch through the adhesive tape. Pull the tape off suddenly. If necessary, repeat the process. Erase the rest with Salamander Trockenreiniger, Woly Gum Special or Coxy Gomme pour Nubuck.