[Walkurie]

When I lived in the cold Northeast, I would try to find an indoor coin-op. Lacking that, I would take a bucket, fill the bucket on 'wash' and then lather down the car. Never used the brushes in the coin-op. After using a clean terry to wash it, went back to the rinse. Dried it as soon as I could, then drove home, Then used a bucket of clean warm water along with another clean terry to remove any residual ice or road dirt.

I'm convinced washing the underside is mostly placebo, especially on the Z4. Had mine up on stands lately and could not believe the surface corrosion on the diff. Okay, I drive half my commute next to the ocean but always avoid the puddles. Still, no road salt, but there was some built-up sand inside the rear diffuser. Don't think a powerwash would have removed that, but it was harmless anyway as the diffuser is plastic.