Humidity Issue mate. Very common in Australia if you do not store the slabs in a temperature controlled space.
Basically it is trapped air pockets within the slab that causes a film of condensation on chromium surfaces.
This is what gives it a wet like look.
Try putting it in a small shoe box or similar, then inside a cool cupboard with some silica gel (desiccant) packs for a week or so. Use 2 or 3 of them and put them inside a slab bag with the slab itself in there too.
Hopefully it works for you, it worked on my Select, Optic, Prizm and Baseball Chrome stuff.
Also, if budget permits.. maybe look into a Humidor. Average one will set you back $600-700.