If it's dirty or just needs a nice cleaning use sadddle-soap, you can added a conditioner if you like but I only use the saddle-soap since it seems to also condition..plus it leaves no residue..wipes clean.
Can you use it on the steering wheel, too? This tends to where faster than the seat leather in past Audis. Just got the C6, steering wheel looks great and would like to keep it that way. Thanks for any advice!