Hi does your instinct has this kind of white residuals? it looks like some side of glass scratches also. They are not going with washing dry water. Can it be a refurbished model?
I am using this for 3 months btw..
If limescale, it'll go with vinegar.
NB. make sure first if safe for the watch to apply. If safe, try diluting with water 50/50 perhaps - then apply with an earbud (the cotton one, not the headphone )