K-Render Cleaning help?

[petelake77]

These large brownish stains on fairly new K-Render. Won't come off with water/washing liquid.

Any help on approach?

https://photos.app.goo.gl/maavVbsqy7itMdHZ7

 

[Pjj]

You need to identify what has caused the stain , it doesn’t look like organic staining but you could try a softwash mix to see if it helps it

 

[ched999uk]

That looks like it's runoff from the wooden frames above trickling through the gap in the sill. Maybe it's an oak frame and it's the Tannin, that said I have no idea how to remove it!