When ripping seams I use a mans mustache trimmer. The one I use is a Wahl brand -it fits my hand. For long seams I have a "third hand" (a little tool that fastens to your table and has a clamp on it to hold one end of the fabric. I think I've seen them called a sewing bird) You can find these in needlework catalogs. Or get your significant other to hold the other end. grin
You just slide the blade down the seam and it clips the threads. Sure saves time when a person messes up a border seam.