I have a long standing customer who fitted replacement windows.
Very smart upvc with a realistic woodgrain effect.
The problem is that, particularly on the North Side, the sills are going green and due to the finish, it's difficult to remove the green.
I've previously used Virosol, a soft cloth, a lot of gentle polishing and then resealing with Super Resin Polish.
Can anyone suggest a painless, de-greening method that isn't going to damage the plastic?