I've never taken one apart, but my sense is that if it is a throw away part you run little risk in taking it apart to see what is going on inside. If it were me, I'd try to remove the mounting bolt first, it looks like if you can get that out of the way, probably by screwing it out, the next step would be to grind off the head of the rivet that appears to hold the housing to what I would guess is an internal mount. If that is the case the housing should lift off the assembly going straight up over the switch. It looks like the housing is bakelite plastic, which is a good hard plastic but it has little flexibility, so be careful, that stuff doesn't just break it kind of shatters.
Keep us posted, love to know what you find out.
Todd