I always use an all purpose cleaner and a scrub brush to get it completely clean then I top with Poorboys Trim Restorer. This combo always works out awesome!
For the all purpose cleaner I have my own Obsessive Detail All Purpose Cleaner/Degreaser. I also carry the Poorboys Trim Restorer. Both products can be found on my website at www.obsessivedetail.com. Let me know if you have anymore questions.