In the first post, where that link goes to, they mention about the smoking, probably why noone here mentioned it.
As far as taking apart your drive to access the lens. First, open the tray, either manually by sticking something (preferably one of those L-shaped tools that come with many drives, but you could use a paperclip as well) into the small lock release hole in the front, or open it before you shut the pc down and unplug it (easier). Other wise, you can't take the front plastic bezel off, and it should come off to take apart the casing easier. Now the front bezel you can release by gently pushing the small plastic clips around the sides of it.
Now you can take apart the metal casing. There should be 4 screws that hold the casing together, take those out. Now pull off the metal cover, (and I think this is what you're talking about?--->>), you notice that the lens is still on the other side, and still not accessible.
I've only seen a couple drives like this, but SOMETIMES there will be 4 more screws now that will release the main drive unit from the metal housing. But USUALLY in almost every case, the main drive unit is already loose, and can now be taken out. All you do, is turn it upside down, so that the main drive "falls out" of the metal housing. Of course be very carefull to "catch" it, and watch where your fingers touch. Try not to touch any chips, metal contacts, etc. keep your fingers on either plastic or metal casing parts if you can.
Sometimes they need a little help dropping out, like VERY slightly flexing out the metal casing so the drive can release to fall out. But usually it's pretty easy to get the drive totally out and clean, just always be careful and gentle of what you're doing. Of course doing any of this voids any warranty if you still had one. I also totally agree with Deer Slayer, the more dust that gets in to the drive, the faster it will die from cleaning issues. Also I would say that some people feed their drives too many dirty discs, if you feed your drive crap, you're gonna get crap back from it soon. I have also fixed quite a few drives just by cleaning them. Most of the time for me, it's been that the lens needs to be cleaned, or the round rubber tire that spins the disc needs cleaning. With the rubber tire, from what I've noticed that if it gets too dirty, it can spin the disc at improper speeds because it has no grip. It will usually react exactly the same as a dirty lens, by maybe telling you theres no disc inserted, or just giving very bad performance and/or errors.