carbon buildup

I keep getting carbon deposits on my distributer points. I have replaced the cap and rotor button and that did the trick but then it started doing it again. The deposits prevent enough spark from getting to the plugs and cause the car to run rich, hesitate, and pretty much run just plain awful.

Any help would be appreciated.

it could be your spark plugs...if they are fouled it would prevent it sparking basically delaying the spark and waisting it in the distributor wires and distributor....i dont know why they would be fouled tho....bad rings maybe...