All right lads, I gave my conservatory roof/gutters a clean with my wfp trolley system for the first time, i got decent results using plain tap water, then did the windows at the end with pure. The edges of the roof where more algae and grime had bult up are still off colour and a bit grey, whats the best thing to do to restore these area? And would it pay to put something in the water ? I used my gardiner sill brush as its the only one i have, is there a brush you would also recommend i got, i plan to start offering it as a service to my regulars. Thanks for reading gents.