We recently construction cleaned a brand new 10,000 square foot office. It has a rubber roof which is stained from all the things going on, such as dirt and rust from where they cut metal and left the shavings there to rust. We tried simple green with scrub brushes which is what the roofer recommended which did not work real well. The contractor wants it done over. I am almost getting into my own pocket on this job. PLEASE HELP!!