My opinion is pretty much the same; I get rid of the dirt and that's it.
Having said that you can try:
1. Get an old brush and cut the bristles down to about 7mm high. Cut the width of the brush to make it smaller. This gives you a real STIFF brush. It will take the skin off your hand. Rub the bristles in Pink Stuff and then scrub the fascia.
2. Get a 'magic eraser pad', cut it, and attach to a Gardiners Quick Lok fitting, using 2 strong elastic bands. This works well, but has to be wet. Just let the end of the pole hose run free, in order to provide lubrication.
It's never failed me, unless the pvc is ingrained.