Westleys bleche white, Used it over 40yrs on car tires, never had whitewalls on motorcycle but use it on my Heritage tires, stock rims. ALWAY READ INSTRUCTIONS on can because I think if overspray is left on paint or alum very long it will burn or mar . But its great on WW and also cleaning blackwalls tires. I have always wet the tire, one at a time, spray carefully, I only spray outer half of tire . Wet a tire brush with water and scrub and hose off the tire immediately then clean up any over spray.
Really makes tires look good and I dont have anything slick on them.

 

start with a good dose of patience and a bike hoist ... after that whatever you do will work.

 

Simple green and Magic Erasers