Ok, this was a tough part for me. The hard plastic needs to be removed till its flat. I first did this with a pair of garden scissors (the small ones) to cut the bulk away, then filed it down till it was smooth and flat. Then I used the soldering iron to melt the plastic away around the cable. After a bit of melting I saw the metal ring and melted away enough plastic to remove it completely. [BE CAREFUL NOT TO MELT THE SHELL OF THE CABLE AND THE PLASTIC TOGETHER]. I then used a nail (thin) and screwdriver (thicker) to push the cable out of the stopper. Took a while but I was able to remove the old cable entirely and reuse the stopper.