Sorry to revive an old thread, but I tried this yesterday... Interesting experience to say the least.
My first comments are, actually getting the headlights out is a complete pig of a job without fairly advanced and specific tools, and don't whatever you do expect to complete this job in a day. I started working on it at 2pm, and didn't finish rebuilding the car until 12pm midnight.
Anyway, once the headlights are actually out, removing the lenses is pretty easy. I went for the heat gun method as opposed to the oven, and the lenses came away nice and easily. Parts to watch out for are the clips for the auto levelling, discovered both of mine were already broken before I even took the headlight out, and the plastic cogs for headlight alignment adjustment, all of these were knackersd on my lights too. I pressed on despite these issues, treating the current headlights as a test project, as it appears I'm going to have to replace them anyway, and got the lights looking really nice, with the lower inserts painted in Matte Black.
Its one of those jobs where, once you know what you're doing, it's pretty easy. My plan is to get two new headlight clusters, properly work on these for a few days to get them looking spot on, and fit them once they're done.