I'm doing the chasing, so my secrets are not as closely guarded
Dawn dish detergent or something similar cleans the wheels and removes the wax.
I have heard car soap will leave the wax intact in the bore, but I do not do this personally on a re-prep; I use Dawn.
I do use alcohol to clean my axles during a reprep, but I do follow that up with Dawn as well.
I have thought of using brake cleaner, but have not yet. I just want to have a repeatable process first, building cars that have a speed consistent with one another. Whatever you do, take notes as to how you do it, stats, on your car, at the times you run, so you can repeat it before changing to something different. At least, that's my approach.
I'm far from the fastest guy out there and each gain for me is getting harder and harder to come by as I get faster. It will take some track time and some specific questions. I'm still learning myself but getting there slowly.
You also might take a look at this thread: http://www.pinewoodderbyonline.com/post/im-in-reprep-hell-6867554?highlight=reprep+hell&trail=15