Can someone identify these marks?

Hello, I washed this customers house about a week ago, and got a call today about marks left on one side(image below). The side was flawless when I left, I’m hoping soap was just stuck and leaked when it rained. It has rained a lot which concerns me as to how there are still marks. I’m going over tomorrow to hopefully fix it. Any idea as to what could have happened? image|230x500

Did you check for oxidation before washing the house ? On all sides ?

There may have been some light oxidation on this side cannot remember fully. I used low pressure so it would not be disturbed. The only thing is it looked great when I was done, Does disturbed oxidation appear days after the siding has been washed?

It is only one section of the house

It’s still wet. Some sidings will look like that for days. Don’t go back tomorrow. Let it dry for a few days and then if any is left clean it with a light mix. Pre-rinse and rinse well after. If it rains again it will look the same.

There are other posts on this from this season.

Confirmed the inevitable; disturbed the oxidation. I must have let the sh dry on the siding. I ordered f13 and am going back asap to fix it. Ive read a couple threads on it, It seems I can downstream the f13 with about 50/50 mix. Is brushing always necessary to remove the oxidation? Hoping I can just downstream the f13 . If not, what brush do you guys recommend? Thanks

New it! Lol anyways a good degreaser, f-19, one restore, clensol bc, all these products work. You will have to brush it all off. Lots of people have the 270 green brush but really any brush works.