On Monday, March 6, 2017 at 8:00:04 PM UTC-8, Electric Comet wrote:
not sure if they are available yet but i would bet they are not far off

self cleaning finishes formulated to be similar to the roof material
...
rain washes away everything that settles on it

The traditional solution is chalking. Some paints are intended to
let loose of the top layer of pigment in normal weathering, which
exposes a clean surface underneath, so to speak. Application thickness
control is very important... There's trees around here is with sticky pollen, that
kind of paint would make the problem wash off easier.