Headlamp Assembly

I know boards/forums like this sometimes have people that tend to encounter the same problem as I am currently having. The headlamp assembly has this nasty dirty foggy look to it and not the clear shiny look it once had. I have been told that these are pretty much sealed except for the hole that the headlight fits into. I have a stiff brush with a sort of coaxial bendy shaft to it that would do the job nicely to get in there with some soap and forceful water stream to get it clean or hopefully would get it clean. That is just my question...I am certain someone on here has had the same problem....so tell me...is the only solution to replace them? I would imagine they wouldn't be cheap so I am willing to try the cleaning method...also how hard are they to remove so I could attempt my cleaning job?

I am new to this board and really welcome the input.