I use nothing but the left over car wash water and an old mitt.
Waxes won't help because the melt at too low a temp.. If you want a good low cost coating for them get a bottle of liquid Nu-Finish. Its an entry level polymer ( $5 US ) and will take the temps put into the wheels by the brakes. Also Klasse AIO followed by SG is good if you already have it. Nu-Finish also leave a very nice gloss and protects for a long while .. soaps won't wash it off but aggressive cleaners will wash EVERYTHING off.
Best thing is to protect and wash often.
Biggest thing is .. no replacement for regular washing. If the dust is left to sit then aggressive cleaners like Simple Green are required.