Cleanout headlight?

Well, I had a headlight bulb explode inside the headlight, spraying it's guts all over. Now, I get dimmer reflection from that light with a new bulb, so I know what I need to do is clean out the headlight.

So-how in the heck do I remove the headlight so I can get the thing cleaned?

Also, should I just use a dishwashing detergent to do the trick (a gnome in my head says no) or what?

If you have a web reference that addresses this, it would be appreciated-please give exact URL if you would.

Thanks!