I think they should let it dry out as much as possible,then coat every single single surface with an epoxy sealant. I wouldn't clean one inch of the car, just seal it up and preserve the "patina" that has built up over the last 50 years. Or possibly restore just half of the car. Seal one entire half of the vehicle exactly as it is today, and then completely restore the other half to the best condition possible. I think that would look great, and make a very interesting project overall, then again I'm might be drunk right now .