i have a 2 yr old aluminum sided trailer , noticed a couple of black streaks after towing in the rain. washed with light detergent and brush it all did not come off, are these streaks algie and would it hurt the siding if ai sprayed with a diluted solution of water and bleach let soak then rinse off. or is this not what the streaks are and is there a easier method of removing them.....
ed hall
ed hall