Havent used a sly mask yet but think they are a dual pane lense.
my son had a new jt dual pane chromo lense.
I cleaned it carefully but washed it under the flow of the tap.
water got between the dual panes and there is no way of getting to it, as trapped between the panes.
:doh:
left lovely streaks across his vision. result I brought him a new lense.
I would use clean water from a spray bottle and a microfibre, again dependent on mask manufacturer always treat the inside of the lense with additional care.