Phew.. Thanks... I always feel under pressure washing, painting and repairing my house! But I always put that down to having to balance on the rail of the 28th Floor at the same time, rather than a Multi-Tasking issue!
I owned a small business in Perth, WA, once. We used pressure/heat washers to clean roof tiles of moss and lichen, etc. Also to get chewing gum off some supermarket forecourts. They do an amazing job, but the good ones (Scandinavian) were expensive to buy. That's all i know!