Scirocco Register

Ok, my rears are in need of attention and a change in color. Is there a way of splitting the rear lense from the rest of the set-up? Has anyone done this/is there a guide?

Any help much appreciated!

carefully!!

not done rears, but opened up the front lens to remove the orange bit quite successfully with a red hot scalpel. glued the lens back onto the back with plumbers solvent cement