The Spectacle Factory recommends, in order, (1) warm water and a microfiber cloth, (2) Zeiss lens wipes, or (3) an ultrasonic bath: https://www.youtube.com/watch?v=m4lJ_5Tg9Ms
They recommend (v=5FUUgO95sb4) against both detergent for the sake of the lens coatings and against sprays which may cause grease to accumulate around the lens rim.
They recommend (v=5FUUgO95sb4) against both detergent for the sake of the lens coatings and against sprays which may cause grease to accumulate around the lens rim.