Staining on roof

stephencl
stephencl Forum Participant Posts: 4
edited November 2014 in Caravans #1

I have a 1996 Compass Reflection , which is kept on my drive. Although the paint work is in good condition on the sides of the caravan .

The van is parked under a tree and the roof i have noticed has started to develop black staining , it seems quite ingrained and caravan  cleaner doesn't remove it. Has anyone got any advice as to treat this.