We tried the house wash cleaner on roof. Took a little of the black spots off but not all. I think with a little more scrubbing they might all be gone. Don't think thats going to happen unless we hire a younger body to do it! LOL Got the MH all washed and looks nice. I got the Meguiar's spray on wipe off. MH still had a nice bead when we washed so thought this would work fine.
Thank you all for all the info and tips.