If possible sandblast your roof.
How to remove oxidation from metal roof.
Pine sap decaying leaves and even road dirt that s drifted into the air can settle on your metal roof and stain it.
To remove severe rust stains.
First the chalk and oxidation need to be scrubbed off.
Metal roofing oxidation removal sandblasting.
Spray this mixture onto the roof and agitate it with a soft bristled brush to get it clean.
For the most.
Most of these substances can be removed by a mixture of cup tri sodium phosphate and 1 gallon of water.
Once the chalk is removed and the metal roof looks good when it is clean and wet then 2 coats of everbrite are applied to restore the color and luster of the roof.
Remove the particles or pieces that are causing the rust stains.
The results will most likely satisfy you.
Modern chemical treatments provide a relatively safe method to use both for you and the environment.