I feel more inclined to help a fellow surfer.
You can do two things. One take of the headlining and pull the tubes out blow some air down there with a compresser.
Or you could spray carb and brake cleaner down there and pour some water in. Open the doors and you will see a little black nipple, this is where the water drains from. I just gave it a good fingering! but you can also use pipe cleaner, or something soft not to damaget the tube.