Up here in the NorthWet, believe it or not, some people with nice cars drive around with the windows down in the Rain, and sometimes forget to put the windows back up and the car sits outside, or better still at Long Term Parking at the airport for several days...
Or, it gets towed and left outside with windows, top, etc., down for days in the rain...
The first time I got one of these, I mistakenly thought it would just be a matter of taking the car apart, drying it all out and reassembly...
I didnt know just how MUCH BMW seat foam absorbs all moisture, takes it in really, deep, and then will NOT release the moisture without a lot of persuasion, and water lift..
It took a huge amount of hours to get all the moisture worked out and extracted from the foam - way more than anyone realized at the Shop and of course, the Client could ever stand to have the car in the Shop...
I spent easily a full work day and more using the Mytee HP60, compressed air, heat, fans, and lots of careful squeezing of the foam and working it to get the water back down to the surface so the Extractor could get it out!
It was a hugely laborious process I would rather not ever have to repeat again... Not having any semblance of Sunlight up here, of course, doesnt help, so putting the seat bottoms outside was out of the question...
Heatlamps, lots of airflow and the Extractor and what seemed like a zillion hours finally got the moisture all out so it was safe to reassemble this 7Series and not have to worry about residual moisture causing mold to grow under the seats on the foam later...
Yeah, another reason, why I am so happy to know I am LEAVING this place forever!!!

Dan F