Stain Removal from Vinyl Siding

[UrbanScrapper]

I had a bucket of CuCl AP solution stored next to the wall of my house. During a heavy rainstorm a tree branch punctured the lid and splashed the AP solution on the siding leaving a brown/green stain. H2O2 doesn't touch it. Neither does a pressure washer. Any suggestions?

 

[butcher]

Trade it for an iron stain? joking but you could.

Caution do not mix products, wash and rinse before trying a different chemical.

You might try phosphoric acid sold as is or used in many products.
CLR calcium lime and rust removers.
oxalic acid or powdered bleaches like OxiClean...
If the materials are porous and the acidic salts have soaked deep into the substate the salts may be very difficult to remove.

 

[Lino1406]

I had a bucket of CuCl AP solution stored next to the wall of my house. During a heavy rainstorm a tree branch punctured the lid and splashed the AP solution on the siding leaving a brown/green stain. H2O2 doesn't touch it. Neither does a pressure washer. Any suggestions?

 

[Lino1406]

Seems copper stains. Try ammmoniac?