Update!! This afternoon I got brave and started over with the embroidery transfers from the 1980's. I pressed at the recommended temp. but I pressed MANY times beyond the suggested 10 seconds. Success!! I also used my Steady Betty underneath. I'm not saying this would work for all older heat transfers but it worked for me. The transfer came out with a dark teal color which is not seen before. So! I've got my heat transfers onto muslin and am ready to embroider!