I had some lovely new oak windows installed last year. The joiner sprayed them with a stain and they look really nice. However the weather has taken its toll and I can see some black marks, which I will wire wool off and restain. My neighbor recently did his with a paint brush and they look really rubbish, he has wrecked them. Anyone have advice on the best way to stain them without wrecking the look. The joiner did a good job with the staining but only put one coat on them.