Has anyone replaced the covers on headlights?

[DCaff300ZX]

As the title suggests, I need some insight from anyone who has replaced the plastic cover on our headlights- my PS cover got a chunk cracked out of it and I have a spare set I can use the cover from, but need to know the easiest way to get the cover separated from the body.
I assume that a new gasket will be needed as well?

[BlackWidowZ]

youre talking about the glass globes or glass housings. Man I have take apart other headlights before and its a pain, but gl man here is the link. It might be easyer to just get a whole new headlight tbh thats what I would do. Here is a guide on how http://www.skylinedesigns.net/z/tech/headlampdisas.php The guide says use a heat gun or put it in the oven i would use the heat gun btw.

[Ace2cool]

Yeah, the outer layer is glass. Unless you're talking about the backside. Either way, it's a HUGE pain.