I had a really hard time also dealing with the white cream interior which if you can handle the upkeep is definitely a beautiful interior. I tried so many different cleaners/conditioners even a steam cleaner. I finally stumbled on Griot's Garage 10994 Leather Care Spray - 22 oz.off amazon for 10.99 which worked wonders for me. After doing half the interior and realizing how much effort it would take to do the front half I bought Cyclo (76-810x2-2PK) Shampoo Brush with Gray Flagged Ultra-Soft Bristles off of amazon and attached it to my porter cable. Seats look close to new now.

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Current
2006 BMW X5 4.8is Dinan S2 Black on Black

Retired
2004 BMW X5 4.8is Black on Cream
2001 Bmw X5 3.0
2006 Bmw 530i
1996 Bmw 328is
1994 Toyota Landcruiser
1989 Bmw 535i