The spiderpoope seems to land neatly on the lower bevels bit of upvc trim near each corner - I use a dot of Astonish upvc cleaer on a damp scouring sponge and give them a quick wipe before starting each window.
Adds a few seconds to each window, but the customers love it, don't seem to get the spiders on the upper floors? or maybe they just dump downstairs?
My pet hate at the mo is slimy snail trails
Dave