the fishing swivels with the hook attached to a non moving surface has been my favorite method. You can cut off the old string at the knot quickly, without damaging anything and the hole stays open while you poke the string through. I use the hole punched in the coro too and the coro folds back together just enough to irritate my shaking fingers as I'm trying to quickly attach streamers between rounds (while simultaneously cleaning out the carb and retaping whatever has broken from the dirt nap/midair that I've usually just experienced).