How to clean the CS interior?

My suggestion would be to utilize a "dry foam" system, this suggestion is a long shot, but see if you can find someone who has a Taski Foam Generator. It's used for carpet cleaning but you can get dry foam from it and put it in a bucket and use a soft upholstery brush to apply it. Basically, you just work the foam in, let it dry and vacuum the surface it was applied to. It does a good job of removing spots and keeping them from wicking back when drying. fyi, the detergent used in that machine (Taski TR101) is certified by the wool institute as "wool safe" which basically means it's a very safe product in terms of it's pH which at dilution is neutral. It's not technically dry, but considerably more dry than a wet extraction. But I would think alcantera would hold up just fine to wet extraction as well. Just make sure whatever detergent or pre-spotter you use has a pH of 7-8. PM me if you have any questions.

 

http://www.ultrasuede.com/about/care/index.html

 

The interior of your car is covered in a synthetic material called, Alcantara. Go here to read care instructions.
http://www.alcantara.com/