Any idea how to clean this?

Customer wanted the edges of the siding where it is dark cleaned, I figured it was some sort of mold so I started with typical 1.5% sh and didn’t budge got my xjet out and went up to 3+% and could not get it to come out, any idea what this could be and how to clean it?

@Innocentbystander long time lurker, figured you might be able to help

Could it be “fallout”?

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It looks like vinyl. Those shakes oxidize. Some folks mess with it and use degreasers and stuff. I don’t. I just tell them it weight come clean. If you put degreaser on to remove oxidation it will look good for a year and then be worse. It strips the wax off, in my opinion

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I think if it was oxydation it would be especially where the sun hits it? In this case i would say fallout…

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Perhaps a dumb question here…but any chance it’s paint overspray from when they painted the eaves and trim?

I’d lean towards the term “fallout” myself but in my limited experience with it I usually see it near areas with lots of dust in the air such as a house that’s bordering a new commercial construction site.


Another thing to check…do any of the neighboring house have a similar “staining”? If so, it’s something from the local environment for sure. Even if that means they all hired a painter who doesn’t tape off areas adequately!

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I thought that as well but customer said that it wasn’t there when they bought the house so couldn’t be paint

Fallout. See it all the time here in Louisville. Dirty air swirls around under the eaves and builds up crap on the siding.

Is it possible to clean?

Yes, search “fallout” on here and look for the long thread by Squid.

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I have this same thing on the siding of my house . I used that 30 second cleaner Home depot sells full strength . And a brush to scrub it off . There’s also a product called 8 ball that I use most of the time to get bugs off someone’s vehicle without damaging the finish . Works great but you have to scrub it . One last thing I have tried that works at least on aluminum is white vinegar with surfactant . But again you have to scrub a little.

OneRestore has worked for me in the past……

Have you tried using a soft bristle brush along with the cleaning solution? That could help remove the mold on the dark edges of the siding. Additionally, you may want to consider using a stronger cleaning solution or seeking the help of a professional


That’s not mold, it’s called ‘atmospheric fallout’ from the wind swirling dirt under the eaves.