Re: If you dunk your fly box, are your flies ruined?
It is worse when fishing salt water or dirty pond water. Last time I saltwater fished I found that even one wet (salty) fly will start to rust whatever is next to it. I rinsed the whole box in fresh water and let it dry out. I let my streamers dry out on a foam patch before putting them back in the box now...
My favorite boxes have a rubber seal that also makes them float.
Using old backing to make a box-leash has been helpful also. The leashes have saved a few of my boxes from being dunked.