However while the polymer material may be able to withstand high winds and harsh uv rays it is still susceptible to staining including a green discoloration caused by one of the following.
Vinal siding bleeding.
To prevent streaking start at the bottom and work up towards the top.
The sun will heat up the nail heads and discolor the vinyl siding.
Rinse with water from top to bottom often as you go to avoid uneven drying and spotting.
Though you want to scrub hard to get rid of the grime be gentle with the siding as too much pressure may crack it.
Usually found on contractor grade siding.
According to the vinyl siding institute the best way is to use a soft cloth or an ordinary long handled soft bristle brush.
Dirt from rain splash up algae lichens mold moss or even smoke or chemical stains have different causes and different preventative measures.
This article discusses common causes of stains or discoloration found on vinyl building siding.
Distinguishing the type of stain found on siding is useful in deciding on the cause and thus the cure or prevention of staining.
A chalky white substance on your vinyl siding and trim is caused by oxidation which occurs most often during damp or wet weather.
Vinyl siding stain diagnosis.
The right way to clean vinyl siding dip the cloth or brush into the solution and scrub the siding until you see noticeable changes.