There are some cleaning solutions offered by www.wash-safe.com which I believe may work well for you.
Todd Miller
2013-01-28 10:10:22.000000
Here in Tallahassee, we have heavy pollen in the spring.
Is there a product you can spray on and rinse off for metal roofing?
My roof is 24ga standing seam with reflective paint, installed 1 year ago.
I do not wish to damage the paint and want to keep my roof looking new.
Jeff Cook
2013-01-28 09:53:48.000000
Thanks for the reply.
I ended up purchasing a long fiberglass extension handle and attached a soft bristle broom to it.
I used a hose end sprayer to apply a mild detergent and then brushed till clean, then rinsed.
I found it worked best on a moist overcast day to give myself time to work the soap and not let it dry out.