The WMs I frequent seem to keep a good stock (in addition to the colors you mention, we also have
ORANGE 
I've had my buckets for better than a year, and they haven't torn up yet.
I wash with them.

(OK, I also use sea sponges, grout sponges, chenile pads and the occasional sheepskin mitt [ooooh that smell

]) If you're hesitant to use them on upper panels, try them for the lower panels first. Or cut them into a size for washing your wheels.