Does anyone else have trouble with a greasy deposit under the door on the sides of you S2K after a rain?

The door has too drain holes in the bottom of the door to drain any water that does get in the door. I always seem to get a grease build up right where those holes are. I took it to the dealership and they replaced the seals on the door thinking that it was just excessive water leaking through and pulling grease or lubricant off of the interal door components (window gears and all).

After the new seals, I continued to have the same problem, so I took it to the dealership again, this time their answer was, "That's normal", it's just pollen and dirt that is collecting from the rainwater moving through the door.

Does anyone else who keeps the car outside notice this buildup?

Do you think the dealership is just avoiding the problem?