I need to wash and stain a porch that originally was a deck but now is a covered porch. The challenge is that the rails now have a screen on the outside of them. I am stumped on how to stain the outside of the rails without getting stain all over the screens. I can get to the outside of the rails and wanted to use a painter's mitt to reach around the back of the rails but how can I prevent a big mess of staining the screens themselves?