Shorten speaker cable

Hello, all,
i have a pair of Harmonic Tech Pro 9 speaker cables, 8’ long, purchased in the late 90’s. They say made in USA, are bi-wire with 2 spades on the amp end and 4 on the speaker end. When I bought them, I was running an integrated amp and now have mono blocks that are staying put. 8’ is just way too long. 3’ would be much better. Is there a place that can cut them down and re-terminate them or is this possibly a DIY project? I would consider terminating the leftovers and selling them cheap. 
Any advice would be greatly appreciated!
Thanks