I have a couple COP boots that are stuck on the plugs. I pulled on them pretty hard, but I'm afraid I will damage them if I pull any harder. I was thinking of shooting some WD-40 down around the outside of the boots and letting it soak for a while. Should I try twisting them, or just pull straight up? It sure would suck if part of it broke off and stayed on the plug. Not sure how I would get that off. Any suggestions?