If you are referring to the type pictured
the answer is yes.
Many folks advised us that you shouldn't get them wet as they are glorified paper. Our rig was new to us and several years old. But as our shades were filthy, what did we have to lose?
We filled our bath tub with warm water and Downy. Let the shades soak for a few minutes, sloshed them around some, attacked stains with a baby's hairbrush and they came out like new! The amount of sand left in the tub was amazing! We then hung the shades outside, closed up to dry. Pretty quick here with 9% humidity
Dry, we then re installed in the rig, sprayed them generously with starch, and closed them up again for the starch to dry.
Very pleasing result for both eye and nose.
Fair Winds and Following Seas