So after developing the dreaded Green Dust Blob problem on my EH-TW 3200, I decided to open it up to try and clean it myself. I believe the Epson 8350 is pretty much the same, so this should work for that also. I managed to get rid of all the dust with this method, so thought I would post this up for others if they want to try it also. It was actually really easy, and I'm happy to have avoided the hassle of having to go the replaced/exchanged route with Epson. All you need is a can of compressed air, a phillips head screwdriver and 20 or so minutes. Obviously, do this at your own risk, I'm not responsible if your projector blows up etc

To start with, make sure your projector is unplugged, and has been off for at least an hour or so.
Step 1
Take out the 2 screws circled in red, then flip the projector upside down.
Step 2
Remove the next twelve screws circled in red.
Step 3
Gently remove the side as shown in the picture. Once you are this far, you need to sort of push it down to disengage the top clips. This is by far the most annoying part of the whole process, be really careful here and do not force anything too much. You can also try flipping the projector right side up and trying to wedge this off that way (it might actually be a little easier like this)
You can see the top clips here, and also the ribbon cable connecting to the 'Menu' panel.
Step 4
With the projector right side up, gently lift off the top casing. This comes off really easily, just be careful of the ribbon cable that is connected.
Step 5
Locate the three ribbons that have the words RED, GREEN and BLUE on them.
They look like this:
Step 6
Spray compressed air as shown in the pictures. (Do all three ribbons just for good measure) I used up a 250ml can while doing this. Try and keep the can as vertical as possible in order to avoid any liquid/moisture coming out of the can. Give it a couple of test sprays before putting it near your projector. You could also get someone to hold the projector on its side while spraying in order to keep the can as upright as possible .
Step 7
Re-assemble, and your blobs will hopefully be gone.
Good luck!