I also use Griot's garage wheel cleaner, I have found that you have to provide some type of agitation no matter what type of cleaner you use. Often times soap and water will do the job with some good old fashioned elbow grease. My new wheels are gunmetallic finish to combat this issue! Good luck.
2015 BMW M4 on order, MW/SO
2013 Porsche 911 Turbo S Guards Red
2013 BMW M5, Retired, AW/SO
2012 VW Golf R daily driven Stage II+ APR tune, 370HP