I use the method Eleanor Burns uses on Quit in a Day. She uses her rotary cutter. Remove a few stitches at the beginning of your seam, holding your rotary cutter like a pencil, carefully touch the threads and pull gently on your seam. You never touch the material just the threads holding your seam together. After a couple of tries, you can open a seam very quickly. I was scared the first couple of times I tried it but now wouldn't do it any other way.