Any sugestions?

[Trailer Trash 2]

I need some ideas on how, and what would be a good way to do this job.
I have done a complete wash and wax of the Monty, I need some sugestions on what might be a good way to wash the rubber roof, without streaking the sides of the Monty from the harsh cleaner chemicals. I dont think Dawn Soap will get the roof clean enugh so a stronger detergent is needed, but that will attack the wax that was put on preavously.
any ideas other than wrapping the sides with painters drop cloth taped to the top channel of the exterour walls.

Thanks for any idea.
don