I generally use car wash soap to clean the wheels. If I need something stronger, I use Meg's All-Wheel cleaner. Once they are clean, I top them off with a couple coats of Poorboy's Wheel Sealant and Meg's High Endurance for the tires. After that, all it takes is car wash soap to clean them.
BTW, if you aren't having luck with a wheel cleaner, clay the wheels like you would your paint. That will remove the embedded contaminants.
Before:
After:
BTW, if you aren't having luck with a wheel cleaner, clay the wheels like you would your paint. That will remove the embedded contaminants.
Before:

After:
