We recommend using our marking products for our garden labels and plant markers. The Black Marking Pencil or Mechanical Greece Pencil are best for the zinc nameplates. For best results, write on the nameplate, then set it in the sun for a day or so. The marking will "bake" onto the nameplate and should last for years. The DecoColor Marker is the best we've found for our copper nameplates. Markings last 2-3 years before beginning to fade.