So, I have an OLD not new mask that constantly fogs, but it fits really well.
Spit doesn't help.
Ammonia plus dishwasher?
Dishwasher first. If that doesn't do it, then ammonia.
My opinion, anyway, after ruining 2 masks with overzealous application of ammonia. Also having now tried some (2 or 3?) new masks with ONLY the dishwasher treatment and no other prep.