I use P21S and Sonax, like everyone else on the forums. But I only use them once in a while; for maintenance washes a microfiber and soapy water gets the bulk off - especially if you seal the rims.
Was: 2008 335xi sedan 6MT Black Sapphire Metallic
Is: 2014 Tesla P85D (Blue Metallic)
Wife's: 2013 Infiniti G37 S sedan 6MT, Black