Combine all spices in a bowl and rub onto roast. I sometimes let my roast marinade in the rub over night.
Place pepper & onion into slow cooker, add roast. I don't use the green pepper.
Combine sauce & brown sugar and pour over meat. Cover and cook on LOW 8-10 hours. Or until you can shred the meat easily with two forks. I normally cook mine 15-20 hrs in crockpot but it should be done much sooner than that.