|Unpicking or frogstitching a 4-thread overlocked/ serged seam can be time consuming. After many years I finally worked out the secret. :)
1. From the right side, run a quick-unpick under the upper looper threads and cut them along the entire length of the seam. It is VERY important that you only cut the upper looper thread and not the lower looper thread as well.
2. Flip your garment over, and from wrong side pull on the lower looper thread. It will unravel as one long thread. Pull the entire seam undone.
3. Flip your garment back to the right side and now pull on the two needle threads. Again they will unravel as two long threads.
4. Lastly, run your finger nail along the seam edge to remove all the cut upper looper threads which are left.
Voila! A frogstitched, overlocked seam in under a minute!