What should you use to clean this watch's screen when a dry microfiber cloth isn't enough?

[PaulQ]

My phones and tablets have screen protectors so my typical 30% alcohol and distilled water mixture is fine. However, I have never had a PLOED (is that what it is?) and it doesn't have a screen protector. What should I use to clean this when a dry microfiber cloth isn't enough?

Thanks!