In reply to Sayon:
Despite being a "north facing" crag, Pillar gets a surprising amount of sun and very few routes stay in the shade. Often the routes look dirty but aren't - the rock is just dark - Al Phizacklea and I did Tapestry and Straights of Messina without having to re-clean them, SoM was the second ascent and several years after the first ascent so things do stay clean.
Stick to routes that are exposed to the breeze, i.e. not grooves, and you should be fine.