More info might help, are you trying to get rid of a specific mark or odour?
AG interior cleaner is pretty good and easy to get hold of, it has good cleaning and odour eliminating properties, best used by either diluting the solution in a bucket of clean warm water or by spraying the diluted solution direct onto a sponge, and work well onto the fabric, remember not to much water as it'll go everywhere and could make the headlining sag!
then dry with either a microfiber or a chamois (the only area of a car where you should use a chamois is to wipe down the interior!)
D