Anyone familiar with Straightwire Black Silc

I recently bought a pair of Straightwire Black Silc cables that were much longer than I needed. My intention ws to remove the poor condition banana plugs, cut the cable to length and reterminate with spades. I've done this before with good results as crimpimg and soldering is something I'm very familiar with. However, these cables use stranded wire that is coated with a substance that isolates each strand. I scraped the cable with a pocet knofe which allowed a continuity check but that didn't remove all of the coating. Also tried heat but this had no noticeable effect. My question is, how can I remove this coating without harming the cable? Anyone done this before.
I will say the cable looks to be very well made.