Mike
  I had a look at the photos. I can't imagine that is road salt. Two
possibilities that come to mind are  a coolant leak in the front
heater core that allows coolant to be blown out of the vents which
condenses on the glass and runs down to the rubber where it
evaporates leaving this crusty buildup or some kind of rubber eating
bacteria "pooping" as it ingests your sealing rubber. Is it only on
the windshield rubber?

On 24-Aug-09, at 12:42 PM, Automatic digest processor wrote:

> Creepy white/tan powder inside windshield rubber