how to disassemble the light switch

[mcoomey]

I'm troubleshooting a problem with my '30 Coupe whereby the low beams suddenly stopped working. When I took apart the light switch to investigate I noticed what I think was a loose horseshoe clip or at least part of it that slipped into the mechanism before I could snag it. It now rattles in the cup behind the black plastic insulator that holds all the wires. My question is how do I remove that insulator from the cup? Is it just pressed into place? I tried tugging on the wires, but didn't want to exert too much force without knowing if there was more to it.