Advice needed, cleaning a few years of dust off a car.

I have a car that has been sitting quite a few years with a build up of dust & some dirt maybe, what would be the best way to clean the outside without scratching the paint? Obviously, a good strong rinsing with a garden hose first. Thanks!

Ignore what everybody is saying about washing that stuff off. Scrape it off and bottle it and sell it on ebay so someone can turn their daily beater into a "Barn Find!"