Shoot us a pic. If it's the actual glass headlight then the only issues can be weather somehow got inside the capsule and corroded or crazed the backing reflector. Perhaps a bulb was used at some point that was not the proper application and burnt the backing.
If it's the large cornering lamp then you may need a plastic restorer kit.
To answer your question the glass can be separated from the can (I believe) by gently heating and pulling the urethane mastic bead.
Headlights are not available new anymore. It looks like they are getting $50-150 each on e-bay.
\'96SS SOB: SSRI, Herter Tune, Tri-Y II, , 3000 Edge, F/HO bars, METCO extendeds with CV MMC, Bilsteins, currently Vredestein Ultrac Sessanta (315/35 rear). Finally, wait for it... LT-4 knock module!
\'96FWB BUW-Butt Ugly White: PCMPerformance tune, HDFA w/ swissed filter, 1/2 SLP s.s. catback with H- and Flow Super 50s, oem opti rebuilt 3 times, SS Bars, METCO LCA, Airlift 1000, Monroe SS, PowerTrax No-Slip, CTS wheels with +1 rubber. Finally, yes again... LT-4 knock module!