The best tip I've seen in a while comes from FichtenFoo. I've always been bad about leaving seams and mold lines on my figures. Metal files work well, but quickly clog with soft lead. Sanding is too clumsy to get into small areas. However, FichtenFoo's sanding sticks have been a real eye-opener here. Quick to make and disposable, they are just the thing for a lot of material removal.