1997 E39 bmw 540i headlight lens

[bmwmedic]

Here is the exact link you need
BMW E39 Non-CELIS Head Light Removal & Lens Cover Relacement
But it seems you mean reflector,not lense
The cover glass becomes foggy from grit and rock chips also, and there are a couple of DIYs for that. Or do you mena the projector lense of xenon lights?
anyway, that linkd describes the removal, check e46fanatics.com for lens polishing
If your relectors are bad, salvage or aftermarket is good but converting to xenon is fairly expensive,assuming you do it correctly and use a projector xenon housing, even if you don't add the whole self leveling feature