Rust Stains from an attic drain

Stains/Surfaces
1

Rust Stains from an Attic Drain. What would be the best method of cleaning Hardieplank siding? Ill try to go by tomorrow and get pictures but it runs down a window all the way down the house, Thanks for any help, I scrolled through the search bar but couldn’t find anything about hardi plank siding.

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I’m guessing you need to test either F-9 or oxalic acid in an inconspicuous spot.

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F9
use a 2:1 ratio
Wet surface before hand, apply, give it a min to work then rinse off
Do not let the F9 dry

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4

White-Ox Rust Remover. Google it.

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Thanks everyone the F9 worked great

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