Larry:
If I remember there are pins in the hinge that need to be knocked out. I have never done this so I would not have any advise other than be careful so you do not break them.
I assume that yours are fogged up? If that is the case, I would suggest that you try brasso on them (you will be amazed). If you have broken parts on the lens where they dog down, that is another issue and they will need to be replaced.