Another roof question!!!!

[av8erdunn]

I know this has been asked numerous time but my searches keep confusing me more since I get conflicting answers. My 02 FR windsong is due for a roof cleaning and sealing. I am wondering if I have an epdm or tpo roof; I am leaning toward epdm since I get white stuff on my knees if I am crawling on the roof. I read tpo will not do that; is that true? If it is indeed a epdm what should I clean it with? I have heard murphys oil soap but once again I read conflicting stories. Some say use oil soap on tpo and not epdm, so I am just getting more confused with every thread I read.

Thanks in advance for the help.