1/8" (3mm) Air Micro Grinder, Pneumatic Pencil Die Grinder, 28000 RPM Free Speed, For Cleaning Dies, Rotors, Backing Plates, Brake Pads, Mounts, Etc.

Neat… so the solution that I would suggest requires a compressor. A pneumatic micro sander pen with a diamond file bit can get into the deepest details and it’s small stroke means that it’s not going to get out of control and damage the subject piece. Remember, It oscillates instead of rotates, so it’s far easier to control and you use a rocking motion on the round surfaces. https://a.co/d/02Arg3w8 You might find a better one