Here's a note from Bonnie Lyn McCaffery, quilter, author, vidcast host, blogger:
I love, love, love doing bobbin embroidery with YLI Candlelight Yarn in the bobbin. I decided to play with this on some notecards. I took regular card stock folded in half and painted it with DecoArt SoSoft Metallic paints. Let dry. Open the card and trim the cover with a decorative rotary cutting blade so the front cover measures 4 1/2" (save the trimmed piece). Close the card and trim the card to 5" x 7".
Load the bobbin with YLI Candlelight Yarn and adjust the bobbin tension so it pulls smoothly but with a little resistance (test on a scrap piece of card stock to be sure stitching lays smooth). On the top of the machine I used YLI Wonder Invisible Thread. I picked a decorative stitch (you might want to experiment on card stock before stitching your beautiful notecards) and stitched it about 1/2" from the bottom edge of the card front. Leave thread tails and glue these to the back side of the card.
I used the trimmed pieces to glue inside the card to give contrast to the front decoratively cut edge. Trim the excess.