You have a couple of options.
First, are you using a stock coil?
If you are you will need to uncrimp the housing of the switch to get the Bakelite contact assembly and wire out(not a easy job).
Second option is not to use a stock coil.
If you are going this route you can just carefully cut the shielded housing off, exposing the inner wire. The inner wire is almost always in good shape a few inches up from the end.
I usually cut the housing at or near where it comes though the firewall.
