I have a picket fence made from pressure treated lumber. The pickets are fastened to the rails with galvanized finish nails set flush to slightly below the surface and unfilled. Furthermore, the fence is about 8 years old and finished with SW solid white stain. The problem at this point is that each nail head (4 per picket) has left a rust spot with a stain surrounding each head. The surrounding stain can be cleaned with a scuff pad but the stain returns.
I plan to restain this spring. Should I: clean, seal and stain or set and fill the holes, seal and stain. Before filling should I seal the nail heads? If so should I use basic wood filler; Bondo, paintable silicone or urethane caulk? I live in NY and am planning on using SW solid acrylic stain again. Any help would be greatly appreciated. Please include specifics like oil, shellac, or latex, along with recommended products and order of operations. Thanks in advanced.