Why do you want to do that? Its not impossible... but that goes into the realm of disassembly instead of just simple maintenence like cleaning the lens. Disassembly is great fun until it comes to the reassembly stage. Then you realize you've lost your laser (I speak from too damn much experience here! )
Well I am going to be honest with you. When I busted my first greenie at my grade 8 science fair, it started to seperate at that point. :-X So before I sent it back I opened that part to see what was in there. ;D
Well, now that that has been admitted to, when it opened at that point it looked as if the collimating lense had been removed, which would look pretty cool to be able to do whenever you wanted! I don't realy care about voiding warranties, but I would only do this if it isn't going to damage the laser.