Jonnysan's power washer seems to be the best idea, so far. But, it still does not solve the problem of cleaning the bottom.
A Smart with a dirty bottom is not Smart at all, especially when it's Michigan or NY road salt.
Since my former days were filled with micro-seconds and micro-waves...
Micro-scratches will not bother me at all.
Wife will be using this car "on the road" (this first winter) and will need to wash it often. As she is all dressed up I know she will not want to run it through a hand wash.
Another solution is needed. I'm still looking!
A2jack