Black spots (1 Viewer)

[Jackomet]

Hi,
Just got back from 9 months in Spain and cleaning the "brown" rain residue off from the rubber roof of my 5er, I find it's covered with small blacks spots between 3 and 10 mm in diameter. Tried my normal cleaner, nope.
What do you reckon? Mould on a rubber roof?
JK

 

[Terry]

Bleach and magic sponge :thumb:
terry