This mixer has not been used for a few years, before using it recently I was washing the "K" beater and dough hook, there is black stuff coming of on to the tea towel, I have washed them several times but to no avail.
It looks like the grease seal from the motor gearbox has failed here, allowing grease drips to enter the mixing bowl. Quite an involved job to replace it I think - presuming you can get the part, of course.
