the latest version of the Cotton IC uses a layer of cotton cloth to cover the core rope and conductors before Teflon is wrapped around the entire assembly to seal everything from air and humidity. I also "kiln dried" the cotton in my oven at 150 degrees before doing all this, just in case there was some moisture in the cotton to begin with. The red cotton strips are from an old flannel sheet - easy to rip into 1-1.5" strips, thin, but does the job to separate the Teflon from the wires below. The cotton should sit nice and tight but doesn't need to be really thick. At the cable ends