How about just a nylon bristle brush and some elbow grease, then rinse with clean water. I have used a toothbrush or this small rectangular brush that I think is supposed to be for scrubbing fingernails.
I wear my water-“proof” watches in the shower because I like to know what time it is. 😉
I tend to get the whitish film mainly on the underside of the band that is against my wrist, probably because it doesn’t get rinsed as well.
#16
I don’t usually let it bother me. However, if you want to get it off without soaping it up, maybe try a stiff toothbrush and warm water?
This works. Ive tried it.