I have found using some sharp scissors, Tamiya sprue cutters, toenail clippers, or a good pair of wire cutters works great. After gettin it cut out, use a good needle file, or emery board to file the edge smooth. It helps if you put a piece of tape on the back side while cutting to make sure the piece doesn't end up on the floor or in an eye. I found out using some clear gloss or clear flat,(depending on what you are attaching it to) works great for small pieces being attached to your model.