Working carefully, tease about 12" of bare lead core out from the braided nylon overcoat. Snip the lead, then pull the braid back up again. Then use that 12" of braid (that no longer has lead wire inside) to tie whatever splicing knot you prefer. t's a little tricky to push the braid back to expose the bare wire, but work patiently and you'll get it. I sometimes build lead-core shoting heads this way for flyfishing, and make a similar splice for lake-trolling set-ups. Hope that's helpful...
--OJ