I've tied a few quilts and like some of the others, I used embroidery floss. My grandma, who normally hand quilted, tied some of her "utility" quilts. She used yarn and after years and years of wear and washing, the yarn kinda turned into fuzzy little balls. LOL I like the embroidery floss better. A friend of mine tied a baby quilt with narrow pink ribbon and tied them into bows, sewing through the knots to keep them tied. It was sooo cute, but I wondered how the bows would look after washing or after a baby chewed on them!