Exactly the issue I have with throttle body cleaning. You take care of the idle problem, and think everything is good. If you notice, almost all of the build up is on the inside of the blade, there is just as much build up throughout the intake, and on the back side of the intake valves, where the injectors don't spray.
Personally I highly recommend an Induction service(and an Injection service for the injectors and combustion chambers, these AJ engines like Carbon), when done properly, it's a night and day difference. However, it's not really a DIY process, as the equipment is expensive. A lot of people will use Seafoam, which will do a pretty good job and cleaning up the wet stuff, but really isn't harsh enough of a chemical, or done in the correct manner to really take care of anything baked on.
Just spraying some cleaner while running won't do that much, as the spray will not be atomized enough to allow it to soak in and do it's job, think of the difference of a humidifier and spraying water through a fan.