This applies particularly to winter time when you may encounter lots of road salt.
If you have decent water pressure to your outside water hoses, and if you have one of those lawn watering devices that sprays in a fan like shape and arcs back and forth, you can take that and slide it under your car and turn it on and at a minimum get the road salt off. It does a decent job at cleaning dirt and such off too.
Ive wanted to find a way to inject a cleaner into the spray so that perhaps you could do a better job of cleaning and degreasing but havent worked on it all that much to see what could be done.