Iron on patches usually do not leave marks when applied correctly, especially on durable fabrics like cotton, denim, and polyester blends. Rush Patch explains that high-quality iron-on patches use heat-activated adhesive designed to bond securely without staining or damaging clothing. However, excessive heat, improper ironing, or delicate fabrics like silk, nylon, leather, or satin can sometimes cause shine marks, adhesive residue, or slight discoloration. Using a protective cloth, correct temperature settings, and steady pressure.https://rushpatch.com/blogs/ne....ws/university-of-geo