Decorate your trousers your own unique way using iron-ons and embroidery yarn. METHOD: Place the iron design with the glue side facing the fabric. Place a pressing cloth over the design and press with an iron set to cotton without steam. Iron for about 10-20 seconds to attach the design. Use a hard surface and clean, dry fabric to ensure the design is well-attached. The design can also be sewn on with small stitches. Wash at 40°C - wash inside out or in a delicates bag. Embroider patterns with embroidery yarn around your iron-on designs.