oxidation stain on brick
FYI, vinyl doesn't oxidize. It has to be aluminum you're referring to in this post. We call it "Paint Wash" up here in PA since it's the run off of water over the oxidized outer layer (paint) of aluminum siding. It usually looks like a white chalk on the brick. No matter how long you hit the stuff with high pressure hot or cold, it doesn't budge. This is a chemistry job, the water is just for rinsing with this stuff.
The best product we have found, and we've tried many, is Diedrich 101 in a 5-1 ratio. Put it on, give a little dwell time of a few minutes and power wash it off hot. Done a bunch of houses and commercial properties this way and they've come out perfect.
Hope that helps!