do you mean opening it up? usually the lens is bonded to the body so you would need to heat it up in order to remove it.
What's the purpose for wanting to open it?>
What's the purpose for wanting to open it?>
There are three ball and socket joints that allow the silver reflector to be aligned correctly the trick to getting them on is that they are all at different angles to each other below is the back of the reflector the bottom socket needs to be pushed vertically downwards (from your description this is the one that's dislodged) the one above it needs to be pulled directly backwards and the third needs to be pushed at about 45 degree once you know which way to push your dislodged one you could be in with a chance of doing it without splitting the headlamp........headlight is fine, but jumped off the pin that is supposed to move it forwards and backwards. It now happily illuminates the sky instead of the road and the screw meant to adjust it is crooked.....
This gives some idea of times and temps that have worked for others, as for the smell I did wait until my wife was out for the day before starting this and it did take two sittings first time I got it started then as it cooled the seal reset so it went back into the oven and redone make sure you pre-heat the oven.....Back to the issue at hand: 20 min @ 125 °C didn't do the trick, so I'm going for 150 next. At 175, it should come loose and the smell should upset anyone in a 100m radius, otherwise I'd be back to square one.