I've only cleaned mine maybe twice in the last year and a half. Used Amway IndustroClean and LOC, sometimes just LOC alone. Basically a grease cutting cleaner and general cleaner mix. Rims cleaned right off with a soft brush followed by car cleaning mitt. Looked same as new when done. Much of that is really road grime, not all brake residue. I get it on both sides of the rear rim even though the brake disk is only on one side. It's more on the rear rim since the exhaust is just in front of the axle, IMHO.
(plus that rear rim is just SO wide so picks up much more.)
I clean mine quite often. First I use one of those California duster mops (the small one, which I think is called dash duster if I remember right??) to get the biggest part off, then I use Lucas Slick Mist next, that gets them cleaned and nice and shinny. I don't understand why the rear wheel gets so nasty on this bike in such a short time??? It's like a blackish/brownish dust that gets all over my rear wheel. The front wheel doesn't get near as dirty as the rear. My rear wheel on my Fury that I had before this bike didn't get nearly as dirty as this one does.
If you have the center stand you can take it to a high pressure washer, put it up on the stand so the rear wheel is over the drain grate and free to spin, then I rotate it by hand on each side while I hit it close up with high pressure soap, works like a charm.