My understanding is that a cleaner will clean off old paint, contaminates(sp?), basically to clean the surface so the wax will "stick" (sorry, lack of a better term). The clay bar is use for cleaning, again, old paint and some of the embedded contaminates that even cleaner can't really get rid of after LOTS of scrubbing. These are almost interchangable?
Now, the polish actually polishes (removes) a layer of the clear coat, thus removing swirls and hair line scratches.
Am I right about these? I don't need to use the polish unless I am trying to remove swirls? As for the little sand like particle that I feel when I run my finger on the car surface, I can get rid of them using a clay bar, right?