I am assuming this is needle turn appliqué? I insert a straight pin into the background and lift it away from the appliqué. Check the front to make sure it's good and make a tiny slit in the background with my scissors. I make the slit by pinching the fabric where I have lifted it with the pin and snip. Once there is a slit for the scissors, I trim away the background leaving a 1/4 seam allowance past the needle turn seam.