I found a tiny howto on the AVS Forum, this however was oriented on the PJ-TX100. I decided to photograph and explain my steps for those who wish to do the same.
The bare minimum is a philips screwdriver. You'll be better of having a few sizes of it, and some plain non-philips screwdrivers. If these are not magnetic, make sure you have something else which is. Otherwise you might spend an hour trying to get a fallen screw back out.
First off, we'll need to remove the cover to get to the inner workings. You'll also remove the lightbulb, as dust may collect their as well.
Remove the cover that houses the lightbulb. Remove the 2 screws holding the lamp, and pull the lamp straight up, using the plastic grips.
After removal, clean it using your pressurized clean air.
On the bottom of the beamer, you'll find 4 screwholes with black screws. and 1 silver screw. Remove the 4 black ones and unscrew the silver one (it won't go out).
Get the beamer back up on it's feet, and remove 2 screws on the back. You'll need to remove the most upperleft and upperright ones. Leave the other ones in place.
Now we'll actually remove the cover. Beware, the controls on the top are attached internally, as depicted (the blue wires) - you'll need to detach it before lifting the cover entirely. You'll have to lift the back (where the connectors are), and lift it up & forward. In my case, I had to shift the lens upwards using the shift-controls on the top. Otherwise the downward facing lens held the cover stuck.
The logic board covers the actual lens and displays. We'll need to disconnect all connectors and unscrew the logic board.
Do not remove the 4 screws on the logic board before removing the connectors; otherwise you won't be able to apply the force needed to remove them.
The logic board is connected to the back of the casing with 2 screws. These are located underneath the video-connector and control-connector. The following picture show the before/after. Do NOT remove any other screws on the back, as you'll probably remove an internal cover. If you do so, this image will show you how this should have been positioned.
Detach all the connectors. The 3 connectors in the center, holding the ribbon-cable require you to first pull back the brown clips on the side.
You can now remove the 4 screws holding the logic board.
Afterwards, lift the logic board upwards. Be carefull not to pull any wires to pieces if they cling to the board.
We can now remove the final cover, thus exposing the inner workings. This is held in place with 4 plastic thingies. You'll also remove the thingie that holds the 3 ribbon cables in place.
You can remove the thingie that holds the 3 ribbon cables in place by squeezing the latches to the center, and pulling it upwards.
4 plastic thingies hold the final cover in place. You can remove these using your nails; just pull upwards.
Then, just pull the final cover upwards; there should be no resistance.
To remove the lens, and be able to clean the actual inside of the displays and filters, you'll need to remove 2 screws.
The 2 screws are located on the top, easily viewable; they are on the left and right of the respectively left and right ribbons; don't remove any of the very small screws.
Unfortunatly, I have no photos of this step. if you have removed the previous 2 screws, you should be able to pull the lens and lens case upwards; it will however be held back by the black metal ring near the end of the lens. I had some trouble removing this; the metal isn't so sturdy, and unscrewing the screws requires some force.
I was able to remove these screws eventually using a plain screwdriver (not philips) and turning it using some pliers.
We can finally remove the lens and lens case. Just pull it upwards; it should come out easily.
DO NOT TOUCH ANYTHING!
Only use clean, pressurized air. You may be wise to clean everything multiple times, saving you the effort of having to open it up again.
Don't waste time; after cleaning, close up quickly to prevent new dust from entering.
Don't forget to clean the airfilter on the side, and the lightbulb & inside of the lightbulb.
Michiel Roding, 2007