I've never bothered to mask off the brush marks on platinum prints, but thought I'd print a few that way to see if portrait clients might like them better, or at least have a choice. My masking worked just fine, and the brush strokes don't show, but the little pencil lines I use to guide the brushing won't erase! A mark from the same pencil applied on the dry print erases easily. First thought was that Pt and/or Pd had combined with the lead in the pencil. The brush strokes cleared just fine. Ideas? What's a better way? The faint pencil marks are pretty ugly.