steam cleaners on a non-skid deck
Borrowed a friend''s small home type steam cleaner (I forget the brand) and tried on deck. With the steam condensing rapidly, it does no harm to the deck. However, doesn''t do much cleaning wise either except it is handy getting some gunk out of crevices. But for the nonskid itself it is just as easy (or easier) to use a general deck wash and scrub brush.
Maybe a rental or other commercial type unit would do better. Doubt it would do any harm but have no personal experience with these types.