Has anyone ever used Starbrite black streak remover or La's Totally Awesome All Purpose Cleaner. I've been cleaning some facia boards and I've tried everything in the van to remove the black water marks, virosol, cif cream cleaner, magic sponges, even cillit bang. Heard good stuff about astonish multi cleaning paste may try that to. The blurb says the Starbrite black streak remover should remove the water marks.