Can I media blast the bottom of my car without taking it all apart and repaint the bottom???

What is the best medium to use and the best paint?
it has a bit of surface rust showing up and I want to nip it in the bud now!

I know of a couple cars were the owners got on their backs with one of those little hand held sand blasters and cleaned up the underside. One car was a 79 Trans Am and the other was a 72 Cutlass 442. I helped put dual exhaust on both cars. They painted the under side black. Those cars turned out great so yes it is possible to do.

What about walnut shells, I would think shells would clean it well enough to spray the bottom but not harm anything.

thanks I just want to clean up the bottom and stop the surface rust from continuing until a few years down the road I can do a rotisserie on her.

Any media that will remove surface rust will be too abrasive and get in places that will harm your car when it is together. Then to recoat things when the car is together will be very tough and you will likely miss places and it will rust even faster.