Well, after 2 years of driving a restored car, radar let me down and I got caught in the rain for 15 minutes, when the radar even said it was not raining where I was. My dilemma is Sand!! The water picked up sand under the body, especially behind the rear valance leaf spring area. Any idea on the best way to remove? Wait until it dries then hit with an air gun? Try now when it is wet? I have the car in a ac garage with 2 fans blowing under it to dry it out... I hate the weather channel app!!! I am a true believer in driving your car but this Rain killed me. I heard flooding the underside is not a good idea to get water in the seams.....thanks for your continued support.

What I would do is put it up on jack stands, ensure it is very secure and steady! get under there with a microfiber cloth and bucket of soapy water and wipe away all the grime.

I wouldn't worry about a "1 time" washing getting everything wet. The car won't rust away from one washing.

Started cleaning and this seems to be working; lightly vacuum with a soft brush attachment, blow off with air compressor, then use detail spray and a microfiber, drink beer, repeat.

you have extra steps , all you need to do is drink beer and repeat

it's not going to melt if it gets wet ...

Power wash with low setting and then blow dry with compressed air. It is only a car DRIVE IT