Junior, it may be hard to tell or see, but they all look like drip stains, not isolated round spots. When Bert goes back he should rub the stains with his finger, oxidation is chalky/ powdery, not like a dirt/wash stain.
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On really old houses with no wall insulation we unzip the vinyl siding and drill a hole every 16 inches or so as needed and dense-pack some cellulose insulation into the wall cavity. It makes a little bit of a mess but after plugging the hole and zipping the vinyl back its a lot better than drilling and filling from inside the house. Paper is bio-degradable.
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Could be a combination of oxidation spots observed, someone trying to powerwash it, etc. 
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One can see where they power washed pointing downward and where they switched to spraying upwards, working the water and the dirt through the weep holes, IMHO.
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I went out today and got my radon monitor and then got up on the roof to troubleshoot this siding on the upper level with the mystery marks.
I could not feel any nail heads under any if the stains and I pulled the ends to see if underlayment was installed and indeed it was. I also felt behind the siding at the ends where stains were close to the ends and no nail head locations correlated to stains
Next I looked up under the edges and found that there are in fact weep holes every 16 inches and over the stains.
Winner winner chicken dinner For Team Larry who were on the drainage theory. Honorable mention for Team Jr because similar marks can be nail-head related so we should always check that, too, when marks like these are observed.
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Thanks for the update, Bert.
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When we all put our heads together, Teamwork, Mystery Solved. 
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Thanks, Bert!
Now, about that chicken dinner… 
I’d meet you in Frankenmuth, Mi for their famous chicken dinners. It is just a little ride north of you on the east side of the lower peninsula of Michigan.
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Hey Larry,
I would love to come up there and have some Famous FrankenChicken with you. I’m warm blooded though so let’s pick a date in the summer when the days are long and I can see your beautiful state without the blanket of snow.
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kind of looks like christmas lights staining or melting im not sure though
So Bert that middle picture…look at the dirt on the inside edge of that siding…there is where Your stains are coming from…and they thought they were doing a good thing by washing it…
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