I want to switch to wax. For preparation, I am cleaning my cassette, the gears in the bicycle derailleur (and the derailleur frame), and the bicycle chainring (I don’t need to clean the chain because I am getting a new one).
For the job, I got white spirit, isopropyl alcohol, and a brush, and I cleaned them as well as I could, but, for example, on the cassette there are still some black dots left and, when touching them, they are still a little greasy. How clean do the components need to be, and how can I get rid of the leftover grease?