I also used a fine point sharpie on my flathead flower pins; I have a 1-30 set and an alphabetical set. However I only use these as I'm cutting my strips. Then I pull a long strip of painter's tape, write the row numbers or letters, tear off and put at the top of each strip. It sticks well to the fabric but leaves no sticky residue. Having them at the top insures I alternate my stitching direction.