When using the Castrol Super Clean. spray the wheel well gererously and then let it dwell for 5 minutes. Spray again with CSC and let it dwell another 5 minutes then hit it with the power washer. If you can put your ride up on jack stands and pull all the wheels, even better, then you can clean most of the front end links, and most of the differential and springs. I've even used it to remove slick rubber. If you can pull your fender liners, do so, it is a lot easier to clean them that way.
Be careful with that stuff, it and its fumes are quite caustic, use long and heavy rubber gloves, eye protection or better yet a face shield, and if the fumes get to you too much, a face mask.
Dont forget the brakes, and since the wheels are off, you can paint the calipers.....