On returning home from holiday I found the roof of my m/h covered in a gritty substance. It appears to have become "baked on" and is proving difficult to remove. I am having to polish, by hand, (long handled brush will not allow sufficient pressure from ladder), using "Silky". As I am unable to reach all parts, particularly the centre of over cab, I wonder if it is possible to stand on roof? The m/h is a Swift Sundance. The roof feels firm but I am not convinced of its strength. Any knowledge of this or any ideas to help ?