P21s was absolutely what my old wheels needed. So clean!!
I had gotten busy, and let the cleaning regimen of my M3 lapse. As a result, my wheels were filthy with brake dust and road grit. Washing with mild car wash soap (as normal) using various brushes, etc. just didn't get rid of the built up grunge. Ordered some P21S (as I heard it was safe), and wow, great results. Spray on, wait a few minutes, wash down, wipe down and they were clean again. Great stuff.
I've used this gel on many different wheels all in different needs of cleaning. P21S has been great for baked on brake dust and has a long cleaning time once applied. It is a little expensive for maintenance washes so I usually reach for this stuff when I'm facing some neglected wheels. Highly recommended.
We've tried nearly every wheel cleaning product over the years and recently decided to try P21S. By far the best product we've ever used! Melts brake dust and does not damage wheels. Great stuff!
A little goes a long way. It cleans well but is gentle enough to be sprayed and left on for hours. In conjunction with a good brush it will be keep your wheels nice and clean. Does not appear to have negative effect on wheel wax/sealant either.