Have never been compelled to entrust the health of my coatings to something as abrasive as a lenspen. Damaged the coating of an MD Rokkor 28 mm F2.8 by applying too much pressure or using an imperfect lens cleaning chamois on receiving it as a Christmas present back when I was a teenager. Cosmetic and minor as the actual damage was, that experience still left a lasting impression to say the least and taught me to be super-sensitive when dealing with delicate lens surfaces. Modern SP Coating has certainly made life easier, but I never try to push my luck anymore.
Haven't used anything apart from meticulously-clean power blowers, microfiber cloths, sensor brushes, and the occasional drop of water (applied to the cloth) for many years and never had any issue.
Last edited by Madaboutpix; 12-26-2020 at 03:14 PM.
Reason: Precision.