well, let's put it this way. the only way they get water in them right now is because they are already leaking. condensation is also a form of leaking. adding a 'vent' hole to the bottom to make sure they drain and breathe will not cause any ill effects, but in turn let them stay clear and dry.
the only other thing you can do is dry them out really good and seal them back up. however, when you do this and then condensation forms, its there to stay since you just sealed the light completely. drilling a hole isnt a bandaid fix, its a permanent one. living in the salt belt would not concern me about having another hole in the light assembly at all.
