Through the years I've tried all sorts of string silencers with varying amounts of success. Cat whiskers, beaver balls, wooly whiskers, etc. By far my favorite and the one I'm still using is Military 550 cord or paracord. Take a piece 2ft long or so and pull the guts out of it. Then cut it up into pieces 2 or 2 1/2 inches long and thread them into your bow string. Four on top and four on bottom seems to be about right for me. As you shoot the nylon unravels and make a very nice and effective silencer. They also last forever. Give it a try.